/*
 * This file is part of aion-lightning <aion-lightning.com>.
 * 
 * aion-lightning is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * aion-lightning is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with aion-lightning.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */
package com.aionemu.commons.utils.internal.chmv8;

import java.util.Arrays;
import java.util.Map;
import java.util.Set;
import java.util.Collection;
import java.util.AbstractMap;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Enumeration;
import java.util.ConcurrentModificationException;
import java.util.NoSuchElementException;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.io.Serializable;

/**
 * A hash table supporting full concurrency of retrievals and high expected concurrency for updates. This class obeys the same functional
 * specification as {@link java.util.Hashtable}, and includes versions of methods corresponding to each method of {@code Hashtable}.
 * However, even though all operations are thread-safe, retrieval operations do <em>not</em> entail locking, and there is <em>not</em> any
 * support for locking the entire table in a way that prevents all access. This class is fully inter-operable with {@code Hashtable} in
 * programs that rely on its thread safety but not on its synchronization details.
 *
 * <p>Retrieval operations (including {@code get}) generally do not block, so may overlap with update operations (including {@code put} and
 * {@code remove}). Retrievals reflect the results of the most recently <em>completed</em> update operations holding upon their onset. (More
 * formally, an update operation for a given key bears a
 * <em>happens-before</em> relation with any (non-null) retrieval for that key reporting the updated value.) For aggregate operations such
 * as {@code putAll} and {@code clear}, concurrent retrievals may reflect insertion or removal of only some entries. Similarly, Iterators
 * and Enumerations return elements reflecting the state of the hash table at some point at or since the creation of the
 * iterator/enumeration. They do <em>not</em> throw {@link
 * ConcurrentModificationException}. However, iterators are designed to be used by only one thread at a time. Bear in mind that the results
 * of aggregate status methods including {@code size}, {@code
 * isEmpty}, and {@code containsValue} are typically useful only when a map is not undergoing concurrent updates in other threads. Otherwise
 * the results of these methods reflect transient states that may be adequate for monitoring or estimation purposes, but not for program
 * control.
 *
 * <p>The table is dynamically expanded when there are too many collisions (i.e., keys that have distinct hash codes but fall into the same
 * slot modulo the table size), with the expected average effect of maintaining roughly two bins per mapping (corresponding to a 0.75 load
 * factor threshold for resizing). There may be much variance around this average as mappings are added and removed, but overall, this
 * maintains a commonly accepted time/space tradeoff for hash tables. However, resizing this or any other kind of hash table may be a
 * relatively slow operation. When possible, it is a good idea to provide a size estimate as an optional {@code
 * initialCapacity} constructor argument. An additional optional {@code loadFactor} constructor argument provides a further means of
 * customizing initial table capacity by specifying the table density to be used in calculating the amount of space to allocate for the
 * given number of elements. Also, for compatibility with previous versions of this class, constructors may optionally specify an expected
 * {@code concurrencyLevel} as an additional hint for internal sizing. Note that using many keys with exactly the same {@code hashCode()} is
 * a sure way to slow down performance of any hash table.
 *
 * <p>A {@link Set} projection of a ConcurrentHashMapV8 may be created (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
 * (using {@link #keySet(Object)} when only keys are of interest, and the mapped values are (perhaps transiently) not used or all take the
 * same mapping value.
 *
 * <p>A ConcurrentHashMapV8 can be used as scalable frequency map (a form of histogram or multiset) by using {@link LongAdder} values and
 * initializing via {@link #computeIfAbsent}. For example, to add a count to a {@code ConcurrentHashMapV8<String,LongAdder> freqs}, you can
 * use {@code freqs.computeIfAbsent(k -> new
 * LongAdder()).increment();}
 *
 * <p>This class and its views and iterators implement all of the
 * <em>optional</em> methods of the {@link Map} and {@link Iterator} interfaces.
 *
 * <p>Like {@link Hashtable} but unlike {@link HashMap}, this class does <em>not</em> allow {@code null} to be used as a key or value.
 *
 * <p>ConcurrentHashMapV8s support sequential and parallel operations bulk operations. (Parallel forms use the {@link
 * ForkJoinPool#commonPool()}). Tasks that may be used in other contexts are available in class {@link ForkJoinTasks}. These operations are
 * designed to be safely, and often sensibly, applied even with maps that are being concurrently updated by other threads; for example, when
 * computing a snapshot summary of the values in a shared registry. There are three kinds of operation, each with four forms, accepting
 * functions with Keys, Values, Entries, and (Key, Value) arguments and/or return values. Because the elements of a ConcurrentHashMapV8 are
 * not ordered in any particular way, and may be processed in different orders in different parallel executions, the correctness of supplied
 * functions should not depend on any ordering, or on any other objects or values that may transiently change while computation is in
 * progress; and except for forEach actions, should ideally be side-effect-free.
 *
 * <ul>
 * <li> forEach: Perform a given action on each element. A variant form applies a given transformation on each element before performing the
 * action.</li>
 *
 * <li> search: Return the first available non-null result of applying a given function on each element; skipping further search when a
 * result is found.</li>
 *
 * <li> reduce: Accumulate each element. The supplied reduction function cannot rely on ordering (more formally, it should be both
 * associative and commutative). There are five variants:
 *
 * <ul>
 *
 * <li> Plain reductions. (There is not a form of this method for (key, value) function arguments since there is no corresponding return
 * type.)</li>
 *
 * <li> Mapped reductions that accumulate the results of a given function applied to each element.</li>
 *
 * <li> Reductions to scalar doubles, longs, and ints, using a given basis value.</li>
 *
 * </li>
 * </ul>
 * </ul>
 *
 * <p>The concurrency properties of bulk operations follow from those of ConcurrentHashMapV8: Any non-null result returned from
 * {@code get(key)} and related access methods bears a happens-before relation with the associated insertion or update. The result of any
 * bulk operation reflects the composition of these per-element relations (but is not necessarily atomic with respect to the map as a whole
 * unless it is somehow known to be quiescent). Conversely, because keys and values in the map are never null, null serves as a reliable
 * atomic indicator of the current lack of any result. To maintain this property, null serves as an implicit basis for all non-scalar
 * reduction operations. For the double, long, and int versions, the basis should be one that, when combined with any other value, returns
 * that other value (more formally, it should be the identity element for the reduction). Most common reductions have these properties; for
 * example, computing a sum with basis 0 or a minimum with basis MAX_VALUE.
 *
 * <p>Search and transformation functions provided as arguments should similarly return null to indicate the lack of any result (in which
 * case it is not used). In the case of mapped reductions, this also enables transformations to serve as filters, returning null (or, in the
 * case of primitive specializations, the identity basis) if the element should not be combined. You can create compound transformations and
 * filterings by composing them yourself under this "null means there is nothing there now" rule before using them in search or reduce
 * operations.
 *
 * <p>Methods accepting and/or returning Entry arguments maintain key-value associations. They may be useful for example when finding the
 * key for the greatest value. Note that "plain" Entry arguments can be supplied using {@code new
 * AbstractMap.SimpleEntry(k,v)}.
 *
 * <p>Bulk operations may complete abruptly, throwing an exception encountered in the application of a supplied function. Bear in mind when
 * handling such exceptions that other concurrently executing functions could also have thrown exceptions, or would have done so if the
 * first exception had not occurred.
 *
 * <p>Speedups for parallel compared to sequential forms are common but not guaranteed. Parallel operations involving brief functions on
 * small maps may execute more slowly than sequential forms if the underlying work to parallelize the computation is more expensive than the
 * computation itself. Similarly, parallelization may not lead to much actual parallelism if all processors are busy performing unrelated
 * tasks.
 *
 * <p>All arguments to all task methods must be non-null.
 *
 * <p><em>jsr166e note: During transition, this class uses nested functional interfaces with different names but the same forms as those
 * expected for JDK8.</em>
 *
 * <p>This class is a member of the
 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
 * Java Collections Framework</a>.
 *
 * @since 1.5
 * @author Doug Lea
 * @param <K> the type of keys maintained by this map
 * @param <V> the type of mapped values
 */
public class ConcurrentHashMapV8<K, V>
				implements ConcurrentMap<K, V>, Serializable {

	private static final long serialVersionUID = 7249069246763182397L;

	/**
	 * A partitionable iterator. A Spliterator can be traversed directly, but can also be partitioned (before traversal) by creating another
	 * Spliterator that covers a non-overlapping portion of the elements, and so may be amenable to parallel execution.
	 *
	 * <p>This interface exports a subset of expected JDK8 functionality.
	 *
	 * <p>Sample usage: Here is one (of the several) ways to compute the sum of the values held in a map using the ForkJoin framework. As
	 * illustrated here, Spliterators are well suited to designs in which a task repeatedly splits off half its work into forked subtasks
	 * until small enough to process directly, and then joins these subtasks. Variants of this style can also be used in completion-based
	 * designs.
	 *
	 * <pre>
	 * {@code ConcurrentHashMapV8<String, Long> m = ...
	 * // split as if have 8 * parallelism, for load balance
	 * int n = m.size();
	 * int p = aForkJoinPool.getParallelism() * 8;
	 * int split = (n < p)? n : p;
	 * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
	 * // ...
	 * static class SumValues extends RecursiveTask<Long> {
	 *   final Spliterator<Long> s;
	 *   final int split;             // split while > 1
	 *   final SumValues nextJoin;    // records forked subtasks to join
	 *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
	 *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
	 *   }
	 *   public Long compute() {
	 *     long sum = 0;
	 *     SumValues subtasks = null; // fork subtasks
	 *     for (int s = split >>> 1; s > 0; s >>>= 1)
	 *       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
	 *     while (s.hasNext())        // directly process remaining elements
	 *       sum += s.next();
	 *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
	 *       sum += t.join();         // collect subtask results
	 *     return sum;
	 *   }
	 * }
	 * }</pre>
	 */
	public static interface Spliterator<T> extends Iterator<T> {

		/**
		 * Returns a Spliterator covering approximately half of the elements, guaranteed not to overlap with those subsequently returned by this
		 * Spliterator. After invoking this method, the current Spliterator will <em>not</em> produce any of the elements of the returned
		 * Spliterator, but the two Spliterators together will produce all of the elements that would have been produced by this Spliterator had
		 * this method not been called. The exact number of elements produced by the returned Spliterator is not guaranteed, and may be zero
		 * (i.e., with {@code hasNext()} reporting {@code
		 * false}) if this Spliterator cannot be further split.
		 *
		 * @return a Spliterator covering approximately half of the elements
		 * @throws IllegalStateException if this Spliterator has already commenced traversing elements
		 */
		Spliterator<T> split();
	}

	/*
	 * Overview:
	 *
	 * The primary design goal of this hash table is to maintain
	 * concurrent readability (typically method get(), but also
	 * iterators and related methods) while minimizing update
	 * contention. Secondary goals are to keep space consumption about
	 * the same or better than java.util.HashMap, and to support high
	 * initial insertion rates on an empty table by many threads.
	 *
	 * Each key-value mapping is held in a Node.  Because Node key
	 * fields can contain special values, they are defined using plain
	 * Object types (not type "K"). This leads to a lot of explicit
	 * casting (and many explicit warning suppressions to tell
	 * compilers not to complain about it). It also allows some of the
	 * public methods to be factored into a smaller number of internal
	 * methods (although sadly not so for the five variants of
	 * put-related operations). The validation-based approach
	 * explained below leads to a lot of code sprawl because
	 * retry-control precludes factoring into smaller methods.
	 *
	 * The table is lazily initialized to a power-of-two size upon the
	 * first insertion.  Each bin in the table normally contains a
	 * list of Nodes (most often, the list has only zero or one Node).
	 * Table accesses require volatile/atomic reads, writes, and
	 * CASes.  Because there is no other way to arrange this without
	 * adding further indirections, we use intrinsics
	 * (sun.misc.Unsafe) operations.  The lists of nodes within bins
	 * are always accurately traversable under volatile reads, so long
	 * as lookups check hash code and non-nullness of value before
	 * checking key equality.
	 *
	 * We use the top (sign) bit of Node hash fields for control
	 * purposes -- it is available anyway because of addressing
	 * constraints.  Nodes with negative hash fields are forwarding
	 * nodes to either TreeBins or resized tables.  The lower 31 bits
	 * of each normal Node's hash field contain a transformation of
	 * the key's hash code.
	 *
	 * Insertion (via put or its variants) of the first node in an
	 * empty bin is performed by just CASing it to the bin.  This is
	 * by far the most common case for put operations under most
	 * key/hash distributions.  Other update operations (insert,
	 * delete, and replace) require locks.  We do not want to waste
	 * the space required to associate a distinct lock object with
	 * each bin, so instead use the first node of a bin list itself as
	 * a lock. Locking support for these locks relies on builtin
	 * "synchronized" monitors.
	 *
	 * Using the first node of a list as a lock does not by itself
	 * suffice though: When a node is locked, any update must first
	 * validate that it is still the first node after locking it, and
	 * retry if not. Because new nodes are always appended to lists,
	 * once a node is first in a bin, it remains first until deleted
	 * or the bin becomes invalidated (upon resizing).  However,
	 * operations that only conditionally update may inspect nodes
	 * until the point of update. This is a converse of sorts to the
	 * lazy locking technique described by Herlihy & Shavit.
	 *
	 * The main disadvantage of per-bin locks is that other update
	 * operations on other nodes in a bin list protected by the same
	 * lock can stall, for example when user equals() or mapping
	 * functions take a long time.  However, statistically, under
	 * random hash codes, this is not a common problem.  Ideally, the
	 * frequency of nodes in bins follows a Poisson distribution
	 * (http://en.wikipedia.org/wiki/Poisson_distribution) with a
	 * parameter of about 0.5 on average, given the resizing threshold
	 * of 0.75, although with a large variance because of resizing
	 * granularity. Ignoring variance, the expected occurrences of
	 * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
	 * first values are:
	 *
	 * 0:    0.60653066
	 * 1:    0.30326533
	 * 2:    0.07581633
	 * 3:    0.01263606
	 * 4:    0.00157952
	 * 5:    0.00015795
	 * 6:    0.00001316
	 * 7:    0.00000094
	 * 8:    0.00000006
	 * more: less than 1 in ten million
	 *
	 * Lock contention probability for two threads accessing distinct
	 * elements is roughly 1 / (8 * #elements) under random hashes.
	 *
	 * Actual hash code distributions encountered in practice
	 * sometimes deviate significantly from uniform randomness.  This
	 * includes the case when N > (1<<30), so some keys MUST collide.
	 * Similarly for dumb or hostile usages in which multiple keys are
	 * designed to have identical hash codes. Also, although we guard
	 * against the worst effects of this (see method spread), sets of
	 * hashes may differ only in bits that do not impact their bin
	 * index for a given power-of-two mask.  So we use a secondary
	 * strategy that applies when the number of nodes in a bin exceeds
	 * a threshold, and at least one of the keys implements
	 * Comparable.  These TreeBins use a balanced tree to hold nodes
	 * (a specialized form of red-black trees), bounding search time
	 * to O(log N).  Each search step in a TreeBin is around twice as
	 * slow as in a regular list, but given that N cannot exceed
	 * (1<<64) (before running out of addresses) this bounds search
	 * steps, lock hold times, etc, to reasonable constants (roughly
	 * 100 nodes inspected per operation worst case) so long as keys
	 * are Comparable (which is very common -- String, Long, etc).
	 * TreeBin nodes (TreeNodes) also maintain the same "next"
	 * traversal pointers as regular nodes, so can be traversed in
	 * iterators in the same way.
	 *
	 * The table is resized when occupancy exceeds a percentage
	 * threshold (nominally, 0.75, but see below).  Any thread
	 * noticing an overfull bin may assist in resizing after the
	 * initiating thread allocates and sets up the replacement
	 * array. However, rather than stalling, these other threads may
	 * proceed with insertions etc.  The use of TreeBins shields us
	 * from the worst case effects of overfilling while resizes are in
	 * progress.  Resizing proceeds by transferring bins, one by one,
	 * from the table to the next table. To enable concurrency, the
	 * next table must be (incrementally) prefilled with place-holders
	 * serving as reverse forwarders to the old table.  Because we are
	 * using power-of-two expansion, the elements from each bin must
	 * either stay at same index, or move with a power of two
	 * offset. We eliminate unnecessary node creation by catching
	 * cases where old nodes can be reused because their next fields
	 * won't change.  On average, only about one-sixth of them need
	 * cloning when a table doubles. The nodes they replace will be
	 * garbage collectable as soon as they are no longer referenced by
	 * any reader thread that may be in the midst of concurrently
	 * traversing table.  Upon transfer, the old table bin contains
	 * only a special forwarding node (with hash field "MOVED") that
	 * contains the next table as its key. On encountering a
	 * forwarding node, access and update operations restart, using
	 * the new table.
	 *
	 * Each bin transfer requires its bin lock, which can stall
	 * waiting for locks while resizing. However, because other
	 * threads can join in and help resize rather than contend for
	 * locks, average aggregate waits become shorter as resizing
	 * progresses.  The transfer operation must also ensure that all
	 * accessible bins in both the old and new table are usable by any
	 * traversal.  This is arranged by proceeding from the last bin
	 * (table.length - 1) up towards the first.  Upon seeing a
	 * forwarding node, traversals (see class Traverser) arrange to
	 * move to the new table without revisiting nodes.  However, to
	 * ensure that no intervening nodes are skipped, bin splitting can
	 * only begin after the associated reverse-forwarders are in
	 * place.
	 *
	 * The traversal scheme also applies to partial traversals of
	 * ranges of bins (via an alternate Traverser constructor)
	 * to support partitioned aggregate operations.  Also, read-only
	 * operations give up if ever forwarded to a null table, which
	 * provides support for shutdown-style clearing, which is also not
	 * currently implemented.
	 *
	 * Lazy table initialization minimizes footprint until first use,
	 * and also avoids resizings when the first operation is from a
	 * putAll, constructor with map argument, or deserialization.
	 * These cases attempt to override the initial capacity settings,
	 * but harmlessly fail to take effect in cases of races.
	 *
	 * The element count is maintained using a specialization of
	 * LongAdder. We need to incorporate a specialization rather than
	 * just use a LongAdder in order to access implicit
	 * contention-sensing that leads to creation of multiple
	 * CounterCells.  The counter mechanics avoid contention on
	 * updates but can encounter cache thrashing if read too
	 * frequently during concurrent access. To avoid reading so often,
	 * resizing under contention is attempted only upon adding to a
	 * bin already holding two or more nodes. Under uniform hash
	 * distributions, the probability of this occurring at threshold
	 * is around 13%, meaning that only about 1 in 8 puts check
	 * threshold (and after resizing, many fewer do so). The bulk
	 * putAll operation further reduces contention by only committing
	 * count updates upon these size checks.
	 *
	 * Maintaining API and serialization compatibility with previous
	 * versions of this class introduces several oddities. Mainly: We
	 * leave untouched but unused constructor arguments refering to
	 * concurrencyLevel. We accept a loadFactor constructor argument,
	 * but apply it only to initial table capacity (which is the only
	 * time that we can guarantee to honor it.) We also declare an
	 * unused "Segment" class that is instantiated in minimal form
	 * only when serializing.
	 */

	/* ---------------- Constants -------------- */
	/**
	 * The largest possible table capacity. This value must be exactly 1<<30 to stay within Java array allocation and indexing bounds for
	 * power of two table sizes, and is further required because the top two bits of 32bit hash fields are used for control purposes.
	 */
	private static final int MAXIMUM_CAPACITY = 1 << 30;
	/**
	 * The default initial table capacity. Must be a power of 2 (i.e., at least 1) and at most MAXIMUM_CAPACITY.
	 */
	private static final int DEFAULT_CAPACITY = 16;
	/**
	 * The largest possible (non-power of two) array size. Needed by toArray and related methods.
	 */
	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
	/**
	 * The default concurrency level for this table. Unused but defined for compatibility with previous versions of this class.
	 */
	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
	/**
	 * The load factor for this table. Overrides of this value in constructors affect only the initial table capacity. The actual floating
	 * point value isn't normally used -- it is simpler to use expressions such as {@code n - (n >>> 2)} for the associated resizing
	 * threshold.
	 */
	private static final float LOAD_FACTOR = 0.75f;
	/**
	 * The bin count threshold for using a tree rather than list for a bin. The value reflects the approximate break-even point for using
	 * tree-based operations.
	 */
	private static final int TREE_THRESHOLD = 8;
	/**
	 * Minimum number of rebinnings per transfer step. Ranges are subdivided to allow multiple resizer threads. This value serves as a lower
	 * bound to avoid resizers encountering excessive memory contention. The value should be at least DEFAULT_CAPACITY.
	 */
	private static final int MIN_TRANSFER_STRIDE = 16;

	/*
	 * Encodings for Node hash fields. See above for explanation.
	 */
	static final int MOVED = 0x80000000; // hash field for forwarding nodes
	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
	/**
	 * Number of CPUS, to place bounds on some sizings
	 */
	static final int NCPU = Runtime.getRuntime().availableProcessors();

	/* ---------------- Counters -------------- */
	// Adapted from LongAdder and Striped64.
	// See their internal docs for explanation.
	// A padded cell for distributing counts
	static final class CounterCell {

		volatile long p0, p1, p2, p3, p4, p5, p6;
		volatile long value;
		volatile long q0, q1, q2, q3, q4, q5, q6;

		CounterCell(long x) {
			value = x;
		}
	}

	/**
	 * Holder for the thread-local hash code determining which CounterCell to use. The code is initialized via the counterHashCodeGenerator,
	 * but may be moved upon collisions.
	 */
	static final class CounterHashCode {

		int code;
	}
	/**
	 * Generates initial value for per-thread CounterHashCodes
	 */
	static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
	/**
	 * Increment for counterHashCodeGenerator. See class ThreadLocal for explanation.
	 */
	static final int SEED_INCREMENT = 0x61c88647;
	/**
	 * Per-thread counter hash codes. Shared across all instances.
	 */
	static final ThreadLocal<CounterHashCode> threadCounterHashCode =
					new ThreadLocal<CounterHashCode>();

	/* ---------------- Fields -------------- */
	/**
	 * The array of bins. Lazily initialized upon first insertion. Size is always a power of two. Accessed directly by iterators.
	 */
	transient volatile Node<V>[] table;
	/**
	 * The next table to use; non-null only while resizing.
	 */
	private transient volatile Node<V>[] nextTable;
	/**
	 * Base counter value, used mainly when there is no contention, but also as a fallback during table initialization races. Updated via CAS.
	 */
	private transient volatile long baseCount;
	/**
	 * Table initialization and resizing control. When negative, the table is being initialized or resized: -1 for initialization, else -(1 +
	 * the number of active resizing threads). Otherwise, when table is null, holds the initial table size to use upon creation, or 0 for
	 * default. After initialization, holds the next element count value upon which to resize the table.
	 */
	private transient volatile int sizeCtl;
	/**
	 * The next table index (plus one) to split while resizing.
	 */
	private transient volatile int transferIndex;
	/**
	 * The least available table index to split while resizing.
	 */
	private transient volatile int transferOrigin;
	/**
	 * Spinlock (locked via CAS) used when resizing and/or creating Cells.
	 */
	private transient volatile int counterBusy;
	/**
	 * Table of counter cells. When non-null, size is a power of 2.
	 */
	private transient volatile CounterCell[] counterCells;
	// views
	private transient KeySetView<K, V> keySet;
	private transient ValuesView<K, V> values;
	private transient EntrySetView<K, V> entrySet;
	/**
	 * For serialization compatibility. Null unless serialized; see below
	 */
	private Segment<K, V>[] segments;

	/* ---------------- Table element access -------------- */

	/*
	 * Volatile access methods are used for table elements as well as
	 * elements of in-progress next table while resizing.  Uses are
	 * null checked by callers, and implicitly bounds-checked, relying
	 * on the invariants that tab arrays have non-zero size, and all
	 * indices are masked with (tab.length - 1) which is never
	 * negative and always less than length. Note that, to be correct
	 * wrt arbitrary concurrency errors by users, bounds checks must
	 * operate on local variables, which accounts for some odd-looking
	 * inline assignments below.
	 */
	@SuppressWarnings("unchecked")
	static final <V> Node<V> tabAt(Node<V>[] tab, int i) { // used by Traverser
		return (Node<V>) U.getObjectVolatile(tab, ((long) i << ASHIFT) + ABASE);
	}

	private static final <V> boolean casTabAt(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
		return U.compareAndSwapObject(tab, ((long) i << ASHIFT) + ABASE, c, v);
	}

	private static final <V> void setTabAt(Node<V>[] tab, int i, Node<V> v) {
		U.putObjectVolatile(tab, ((long) i << ASHIFT) + ABASE, v);
	}

	/* ---------------- Nodes -------------- */
	/**
	 * Key-value entry. Note that this is never exported out as a user-visible Map.Entry (see MapEntry below). Nodes with a hash field of
	 * MOVED are special, and do not contain user keys or values. Otherwise, keys are never null, and null val fields indicate that a node is
	 * in the process of being deleted or created. For purposes of read-only access, a key may be read before a val, but can only be used
	 * after checking val to be non-null.
	 */
	static class Node<V> {

		final int hash;
		final Object key;
		volatile V val;
		volatile Node<V> next;

		Node(int hash, Object key, V val, Node<V> next) {
			this.hash = hash;
			this.key = key;
			this.val = val;
			this.next = next;
		}
	}

	/* ---------------- TreeBins -------------- */
	/**
	 * Nodes for use in TreeBins
	 */
	static final class TreeNode<V> extends Node<V> {

		TreeNode<V> parent;  // red-black tree links
		TreeNode<V> left;
		TreeNode<V> right;
		TreeNode<V> prev;    // needed to unlink next upon deletion
		boolean red;

		TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
			super(hash, key, val, next);
			this.parent = parent;
		}
	}

	/**
	 * A specialized form of red-black tree for use in bins whose size exceeds a threshold.
	 *
	 * TreeBins use a special form of comparison for search and related operations (which is the main reason we cannot use existing
	 * collections such as TreeMaps). TreeBins contain Comparable elements, but may contain others, as well as elements that are Comparable
	 * but not necessarily Comparable<T>
	 * for the same T, so we cannot invoke compareTo among them. To handle this, the tree is ordered primarily by hash value, then by
	 * getClass().getName() order, and then by Comparator order among elements of the same class. On lookup at a node, if elements are not
	 * comparable or compare as 0, both left and right children may need to be searched in the case of tied hash values. (This corresponds to
	 * the full list search that would be necessary if all elements were non-Comparable and had tied hashes.) The red-black balancing code is
	 * updated from pre-jdk-collections (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) based in turn on Cormen, Leiserson, and
	 * Rivest "Introduction to Algorithms" (CLR).
	 *
	 * TreeBins also maintain a separate locking discipline than regular bins. Because they are forwarded via special MOVED nodes at bin heads
	 * (which can never change once established), we cannot use those nodes as locks. Instead, TreeBin extends AbstractQueuedSynchronizer to
	 * support a simple form of read-write lock. For update operations and table validation, the exclusive form of lock behaves in the same
	 * way as bin-head locks. However, lookups use shared read-lock mechanics to allow multiple readers in the absence of writers.
	 * Additionally, these lookups do not ever block: While the lock is not available, they proceed along the slow traversal path (via
	 * next-pointers) until the lock becomes available or the list is exhausted, whichever comes first. (These cases are not fast, but
	 * maximize aggregate expected throughput.) The AQS mechanics for doing this are straightforward. The lock state is held as AQS
	 * getState(). Read counts are negative; the write count (1) is positive. There are no signalling preferences among readers and writers.
	 * Since we don't need to export full Lock API, we just override the minimal AQS methods and use them directly.
	 */
	static final class TreeBin<V> extends AbstractQueuedSynchronizer {

		private static final long serialVersionUID = 2249069246763182397L;
		transient TreeNode<V> root;  // root of tree
		transient TreeNode<V> first; // head of next-pointer list

		/* AQS overrides */
		public final boolean isHeldExclusively() {
			return getState() > 0;
		}

		public final boolean tryAcquire(int ignore) {
			if (compareAndSetState(0, 1)) {
				setExclusiveOwnerThread(Thread.currentThread());
				return true;
			}
			return false;
		}

		public final boolean tryRelease(int ignore) {
			setExclusiveOwnerThread(null);
			setState(0);
			return true;
		}

		public final int tryAcquireShared(int ignore) {
			for (int c;;) {
				if ((c = getState()) > 0)
					return -1;
				if (compareAndSetState(c, c - 1))
					return 1;
			}
		}

		public final boolean tryReleaseShared(int ignore) {
			int c;
			do {
			}
			while (!compareAndSetState(c = getState(), c + 1));
			return c == -1;
		}

		/**
		 * From CLR
		 */
		private void rotateLeft(TreeNode<V> p) {
			if (p != null) {
				TreeNode<V> r = p.right, pp, rl;
				if ((rl = p.right = r.left) != null)
					rl.parent = p;
				if ((pp = r.parent = p.parent) == null)
					root = r;
				else if (pp.left == p)
					pp.left = r;
				else
					pp.right = r;
				r.left = p;
				p.parent = r;
			}
		}

		/**
		 * From CLR
		 */
		private void rotateRight(TreeNode<V> p) {
			if (p != null) {
				TreeNode<V> l = p.left, pp, lr;
				if ((lr = p.left = l.right) != null)
					lr.parent = p;
				if ((pp = l.parent = p.parent) == null)
					root = l;
				else if (pp.right == p)
					pp.right = l;
				else
					pp.left = l;
				l.right = p;
				p.parent = l;
			}
		}

		/**
		 * Returns the TreeNode (or null if not found) for the given key starting at given root.
		 */
		@SuppressWarnings("unchecked")
		final TreeNode<V> getTreeNode(int h, Object k, TreeNode<V> p) {
			Class<?> c = k.getClass();
			while (p != null) {
				int dir, ph;
				Object pk;
				Class<?> pc;
				if ((ph = p.hash) == h) {
					if ((pk = p.key) == k || k.equals(pk))
						return p;
					if (c != (pc = pk.getClass())
									|| !(k instanceof Comparable)
									|| (dir = ((Comparable) k).compareTo((Comparable) pk)) == 0) {
						if ((dir = (c == pc) ? 0
										: c.getName().compareTo(pc.getName())) == 0) {
							TreeNode<V> r = null, pl, pr; // check both sides
							if ((pr = p.right) != null && h >= pr.hash
											&& (r = getTreeNode(h, k, pr)) != null)
								return r;
							else if ((pl = p.left) != null && h <= pl.hash)
								dir = -1;
							else // nothing there
								return null;
						}
					}
				}
				else
					dir = (h < ph) ? -1 : 1;
				p = (dir > 0) ? p.right : p.left;
			}
			return null;
		}

		/**
		 * Wrapper for getTreeNode used by CHM.get. Tries to obtain read-lock to call getTreeNode, but during failure to get lock, searches
		 * along next links.
		 */
		final V getValue(int h, Object k) {
			Node<V> r = null;
			int c = getState(); // Must read lock state first
			for (Node<V> e = first; e != null; e = e.next) {
				if (c <= 0 && compareAndSetState(c, c - 1)) {
					try {
						r = getTreeNode(h, k, root);
					}
					finally {
						releaseShared(0);
					}
					break;
				}
				else if (e.hash == h && k.equals(e.key)) {
					r = e;
					break;
				}
				else
					c = getState();
			}
			return r == null ? null : r.val;
		}

		/**
		 * Finds or adds a node.
		 *
		 * @return null if added
		 */
		@SuppressWarnings("unchecked")
		final TreeNode<V> putTreeNode(int h, Object k, V v) {
			Class<?> c = k.getClass();
			TreeNode<V> pp = root, p = null;
			int dir = 0;
			while (pp != null) { // find existing node or leaf to insert at
				int ph;
				Object pk;
				Class<?> pc;
				p = pp;
				if ((ph = p.hash) == h) {
					if ((pk = p.key) == k || k.equals(pk))
						return p;
					if (c != (pc = pk.getClass())
									|| !(k instanceof Comparable)
									|| (dir = ((Comparable) k).compareTo((Comparable) pk)) == 0) {
						TreeNode<V> s = null, r = null, pr;
						if ((dir = (c == pc) ? 0
										: c.getName().compareTo(pc.getName())) == 0) {
							if ((pr = p.right) != null && h >= pr.hash
											&& (r = getTreeNode(h, k, pr)) != null)
								return r;
							else // continue left
								dir = -1;
						}
						else if ((pr = p.right) != null && h >= pr.hash)
							s = pr;
						if (s != null && (r = getTreeNode(h, k, s)) != null)
							return r;
					}
				}
				else
					dir = (h < ph) ? -1 : 1;
				pp = (dir > 0) ? p.right : p.left;
			}

			TreeNode<V> f = first;
			TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
			if (p == null)
				root = x;
			else { // attach and rebalance; adapted from CLR
				TreeNode<V> xp, xpp;
				if (f != null)
					f.prev = x;
				if (dir <= 0)
					p.left = x;
				else
					p.right = x;
				x.red = true;
				while (x != null && (xp = x.parent) != null && xp.red
								&& (xpp = xp.parent) != null) {
					TreeNode<V> xppl = xpp.left;
					if (xp == xppl) {
						TreeNode<V> y = xpp.right;
						if (y != null && y.red) {
							y.red = false;
							xp.red = false;
							xpp.red = true;
							x = xpp;
						}
						else {
							if (x == xp.right) {
								rotateLeft(x = xp);
								xpp = (xp = x.parent) == null ? null : xp.parent;
							}
							if (xp != null) {
								xp.red = false;
								if (xpp != null) {
									xpp.red = true;
									rotateRight(xpp);
								}
							}
						}
					}
					else {
						TreeNode<V> y = xppl;
						if (y != null && y.red) {
							y.red = false;
							xp.red = false;
							xpp.red = true;
							x = xpp;
						}
						else {
							if (x == xp.left) {
								rotateRight(x = xp);
								xpp = (xp = x.parent) == null ? null : xp.parent;
							}
							if (xp != null) {
								xp.red = false;
								if (xpp != null) {
									xpp.red = true;
									rotateLeft(xpp);
								}
							}
						}
					}
				}
				TreeNode<V> r = root;
				if (r != null && r.red)
					r.red = false;
			}
			return null;
		}

		/**
		 * Removes the given node, that must be present before this call. This is messier than typical red-black deletion code because we cannot
		 * swap the contents of an interior node with a leaf successor that is pinned by "next" pointers that are accessible independently of
		 * lock. So instead we swap the tree linkages.
		 */
		final void deleteTreeNode(TreeNode<V> p) {
			TreeNode<V> next = (TreeNode<V>) p.next; // unlink traversal pointers
			TreeNode<V> pred = p.prev;
			if (pred == null)
				first = next;
			else
				pred.next = next;
			if (next != null)
				next.prev = pred;
			TreeNode<V> replacement;
			TreeNode<V> pl = p.left;
			TreeNode<V> pr = p.right;
			if (pl != null && pr != null) {
				TreeNode<V> s = pr, sl;
				while ((sl = s.left) != null) // find successor
					s = sl;
				boolean c = s.red;
				s.red = p.red;
				p.red = c; // swap colors
				TreeNode<V> sr = s.right;
				TreeNode<V> pp = p.parent;
				if (s == pr) { // p was s's direct parent
					p.parent = s;
					s.right = p;
				}
				else {
					TreeNode<V> sp = s.parent;
					if ((p.parent = sp) != null) {
						if (s == sp.left)
							sp.left = p;
						else
							sp.right = p;
					}
					if ((s.right = pr) != null)
						pr.parent = s;
				}
				p.left = null;
				if ((p.right = sr) != null)
					sr.parent = p;
				if ((s.left = pl) != null)
					pl.parent = s;
				if ((s.parent = pp) == null)
					root = s;
				else if (p == pp.left)
					pp.left = s;
				else
					pp.right = s;
				replacement = sr;
			}
			else
				replacement = (pl != null) ? pl : pr;
			TreeNode<V> pp = p.parent;
			if (replacement == null) {
				if (pp == null) {
					root = null;
					return;
				}
				replacement = p;
			}
			else {
				replacement.parent = pp;
				if (pp == null)
					root = replacement;
				else if (p == pp.left)
					pp.left = replacement;
				else
					pp.right = replacement;
				p.left = p.right = p.parent = null;
			}
			if (!p.red) { // rebalance, from CLR
				TreeNode<V> x = replacement;
				while (x != null) {
					TreeNode<V> xp, xpl;
					if (x.red || (xp = x.parent) == null) {
						x.red = false;
						break;
					}
					if (x == (xpl = xp.left)) {
						TreeNode<V> sib = xp.right;
						if (sib != null && sib.red) {
							sib.red = false;
							xp.red = true;
							rotateLeft(xp);
							sib = (xp = x.parent) == null ? null : xp.right;
						}
						if (sib == null)
							x = xp;
						else {
							TreeNode<V> sl = sib.left, sr = sib.right;
							if ((sr == null || !sr.red)
											&& (sl == null || !sl.red)) {
								sib.red = true;
								x = xp;
							}
							else {
								if (sr == null || !sr.red) {
									if (sl != null)
										sl.red = false;
									sib.red = true;
									rotateRight(sib);
									sib = (xp = x.parent) == null
													? null : xp.right;
								}
								if (sib != null) {
									sib.red = (xp == null) ? false : xp.red;
									if ((sr = sib.right) != null)
										sr.red = false;
								}
								if (xp != null) {
									xp.red = false;
									rotateLeft(xp);
								}
								x = root;
							}
						}
					}
					else { // symmetric
						TreeNode<V> sib = xpl;
						if (sib != null && sib.red) {
							sib.red = false;
							xp.red = true;
							rotateRight(xp);
							sib = (xp = x.parent) == null ? null : xp.left;
						}
						if (sib == null)
							x = xp;
						else {
							TreeNode<V> sl = sib.left, sr = sib.right;
							if ((sl == null || !sl.red)
											&& (sr == null || !sr.red)) {
								sib.red = true;
								x = xp;
							}
							else {
								if (sl == null || !sl.red) {
									if (sr != null)
										sr.red = false;
									sib.red = true;
									rotateLeft(sib);
									sib = (xp = x.parent) == null
													? null : xp.left;
								}
								if (sib != null) {
									sib.red = (xp == null) ? false : xp.red;
									if ((sl = sib.left) != null)
										sl.red = false;
								}
								if (xp != null) {
									xp.red = false;
									rotateRight(xp);
								}
								x = root;
							}
						}
					}
				}
			}
			if (p == replacement && (pp = p.parent) != null) {
				if (p == pp.left) // detach pointers
					pp.left = null;
				else if (p == pp.right)
					pp.right = null;
				p.parent = null;
			}
		}
	}

	/* ---------------- Collision reduction methods -------------- */
	/**
	 * Spreads higher bits to lower, and also forces top bit to 0. Because the table uses power-of-two masking, sets of hashes that vary only
	 * in bits above the current mask will always collide. (Among known examples are sets of Float keys holding consecutive whole numbers in
	 * small tables.) To counter this, we apply a transform that spreads the impact of higher bits downward. There is a tradeoff between
	 * speed, utility, and quality of bit-spreading. Because many common sets of hashes are already reasonably distributed across bits (so
	 * don't benefit from spreading), and because we use trees to handle large sets of collisions in bins, we don't need excessively high
	 * quality.
	 */
	private static final int spread(int h) {
		h ^= (h >>> 18) ^ (h >>> 12);
		return (h ^ (h >>> 10)) & HASH_BITS;
	}

	/**
	 * Replaces a list bin with a tree bin if key is comparable. Call only when locked.
	 */
	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
		if (key instanceof Comparable) {
			TreeBin<V> t = new TreeBin<V>();
			for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
				t.putTreeNode(e.hash, e.key, e.val);
			setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
		}
	}

	/* ---------------- Internal access and update methods -------------- */
	/**
	 * Implementation for get and containsKey
	 */
	@SuppressWarnings("unchecked")
	private final V internalGet(Object k) {
		int h = spread(k.hashCode());
		retry:
		for (Node<V>[] tab = table; tab != null;) {
			Node<V> e;
			Object ek;
			V ev;
			int eh; // locals to read fields once
			for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
				if ((eh = e.hash) < 0) {
					if ((ek = e.key) instanceof TreeBin)  // search TreeBin
						return ((TreeBin<V>) ek).getValue(h, k);
					else {                      // restart with new table
						tab = (Node<V>[]) ek;
						continue retry;
					}
				}
				else if (eh == h && (ev = e.val) != null
								&& ((ek = e.key) == k || k.equals(ek)))
					return ev;
			}
			break;
		}
		return null;
	}

	/**
	 * Implementation for the four public remove/replace methods: Replaces node value with v, conditional upon match of cv if non-null. If
	 * resulting value is null, delete.
	 */
	@SuppressWarnings("unchecked")
	private final V internalReplace(Object k, V v, Object cv) {
		int h = spread(k.hashCode());
		V oldVal = null;
		for (Node<V>[] tab = table;;) {
			Node<V> f;
			int i, fh;
			Object fk;
			if (tab == null
							|| (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
				break;
			else if ((fh = f.hash) < 0) {
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					boolean validated = false;
					boolean deleted = false;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							validated = true;
							TreeNode<V> p = t.getTreeNode(h, k, t.root);
							if (p != null) {
								V pv = p.val;
								if (cv == null || cv == pv || cv.equals(pv)) {
									oldVal = pv;
									if ((p.val = v) == null) {
										deleted = true;
										t.deleteTreeNode(p);
									}
								}
							}
						}
					}
					finally {
						t.release(0);
					}
					if (validated) {
						if (deleted)
							addCount(-1L, -1);
						break;
					}
				}
				else
					tab = (Node<V>[]) fk;
			}
			else if (fh != h && f.next == null) // precheck
				break;                          // rules out possible existence
			else {
				boolean validated = false;
				boolean deleted = false;
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						validated = true;
						for (Node<V> e = f, pred = null;;) {
							Object ek;
							V ev;
							if (e.hash == h
											&& ((ev = e.val) != null)
											&& ((ek = e.key) == k || k.equals(ek))) {
								if (cv == null || cv == ev || cv.equals(ev)) {
									oldVal = ev;
									if ((e.val = v) == null) {
										deleted = true;
										Node<V> en = e.next;
										if (pred != null)
											pred.next = en;
										else
											setTabAt(tab, i, en);
									}
								}
								break;
							}
							pred = e;
							if ((e = e.next) == null)
								break;
						}
					}
				}
				if (validated) {
					if (deleted)
						addCount(-1L, -1);
					break;
				}
			}
		}
		return oldVal;
	}

	/*
	 * Internal versions of insertion methods
	 * All have the same basic structure as the first (internalPut):
	 *  1. If table uninitialized, create
	 *  2. If bin empty, try to CAS new node
	 *  3. If bin stale, use new table
	 *  4. if bin converted to TreeBin, validate and relay to TreeBin methods
	 *  5. Lock and validate; if valid, scan and add or update
	 *
	 * The putAll method differs mainly in attempting to pre-allocate
	 * enough table space, and also more lazily performs count updates
	 * and checks.
	 *
	 * Most of the function-accepting methods can't be factored nicely
	 * because they require different functional forms, so instead
	 * sprawl out similar mechanics.
	 */
	/**
	 * Implementation for put and putIfAbsent
	 */
	@SuppressWarnings("unchecked")
	private final V internalPut(K k, V v, boolean onlyIfAbsent) {
		if (k == null || v == null)
			throw new NullPointerException();
		int h = spread(k.hashCode());
		int len = 0;
		for (Node<V>[] tab = table;;) {
			int i, fh;
			Node<V> f;
			Object fk;
			V fv;
			if (tab == null)
				tab = initTable();
			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
				if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
					break;                   // no lock when adding to empty bin
			}
			else if ((fh = f.hash) < 0) {
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					V oldVal = null;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							len = 2;
							TreeNode<V> p = t.putTreeNode(h, k, v);
							if (p != null) {
								oldVal = p.val;
								if (!onlyIfAbsent)
									p.val = v;
							}
						}
					}
					finally {
						t.release(0);
					}
					if (len != 0) {
						if (oldVal != null)
							return oldVal;
						break;
					}
				}
				else
					tab = (Node<V>[]) fk;
			}
			else if (onlyIfAbsent && fh == h && (fv = f.val) != null
							&& ((fk = f.key) == k || k.equals(fk))) // peek while nearby
				return fv;
			else {
				V oldVal = null;
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						len = 1;
						for (Node<V> e = f;; ++len) {
							Object ek;
							V ev;
							if (e.hash == h
											&& (ev = e.val) != null
											&& ((ek = e.key) == k || k.equals(ek))) {
								oldVal = ev;
								if (!onlyIfAbsent)
									e.val = v;
								break;
							}
							Node<V> last = e;
							if ((e = e.next) == null) {
								last.next = new Node<V>(h, k, v, null);
								if (len >= TREE_THRESHOLD)
									replaceWithTreeBin(tab, i, k);
								break;
							}
						}
					}
				}
				if (len != 0) {
					if (oldVal != null)
						return oldVal;
					break;
				}
			}
		}
		addCount(1L, len);
		return null;
	}

	/**
	 * Implementation for computeIfAbsent
	 */
	@SuppressWarnings("unchecked")
	private final V internalComputeIfAbsent(K k, Fun<? super K, ? extends V> mf) {
		if (k == null || mf == null)
			throw new NullPointerException();
		int h = spread(k.hashCode());
		V val = null;
		int len = 0;
		for (Node<V>[] tab = table;;) {
			Node<V> f;
			int i;
			Object fk;
			if (tab == null)
				tab = initTable();
			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
				Node<V> node = new Node<V>(h, k, null, null);
				synchronized (node) {
					if (casTabAt(tab, i, null, node)) {
						len = 1;
						try {
							if ((val = mf.apply(k)) != null)
								node.val = val;
						}
						finally {
							if (val == null)
								setTabAt(tab, i, null);
						}
					}
				}
				if (len != 0)
					break;
			}
			else if (f.hash < 0) {
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					boolean added = false;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							len = 1;
							TreeNode<V> p = t.getTreeNode(h, k, t.root);
							if (p != null)
								val = p.val;
							else if ((val = mf.apply(k)) != null) {
								added = true;
								len = 2;
								t.putTreeNode(h, k, val);
							}
						}
					}
					finally {
						t.release(0);
					}
					if (len != 0) {
						if (!added)
							return val;
						break;
					}
				}
				else
					tab = (Node<V>[]) fk;
			}
			else {
				for (Node<V> e = f; e != null; e = e.next) { // prescan
					Object ek;
					V ev;
					if (e.hash == h && (ev = e.val) != null
									&& ((ek = e.key) == k || k.equals(ek)))
						return ev;
				}
				boolean added = false;
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						len = 1;
						for (Node<V> e = f;; ++len) {
							Object ek;
							V ev;
							if (e.hash == h
											&& (ev = e.val) != null
											&& ((ek = e.key) == k || k.equals(ek))) {
								val = ev;
								break;
							}
							Node<V> last = e;
							if ((e = e.next) == null) {
								if ((val = mf.apply(k)) != null) {
									added = true;
									last.next = new Node<V>(h, k, val, null);
									if (len >= TREE_THRESHOLD)
										replaceWithTreeBin(tab, i, k);
								}
								break;
							}
						}
					}
				}
				if (len != 0) {
					if (!added)
						return val;
					break;
				}
			}
		}
		if (val != null)
			addCount(1L, len);
		return val;
	}

	/**
	 * Implementation for compute
	 */
	@SuppressWarnings("unchecked")
	private final V internalCompute(K k, boolean onlyIfPresent,
					BiFun<? super K, ? super V, ? extends V> mf) {
		if (k == null || mf == null)
			throw new NullPointerException();
		int h = spread(k.hashCode());
		V val = null;
		int delta = 0;
		int len = 0;
		for (Node<V>[] tab = table;;) {
			Node<V> f;
			int i, fh;
			Object fk;
			if (tab == null)
				tab = initTable();
			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
				if (onlyIfPresent)
					break;
				Node<V> node = new Node<V>(h, k, null, null);
				synchronized (node) {
					if (casTabAt(tab, i, null, node)) {
						try {
							len = 1;
							if ((val = mf.apply(k, null)) != null) {
								node.val = val;
								delta = 1;
							}
						}
						finally {
							if (delta == 0)
								setTabAt(tab, i, null);
						}
					}
				}
				if (len != 0)
					break;
			}
			else if ((fh = f.hash) < 0) {
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							len = 1;
							TreeNode<V> p = t.getTreeNode(h, k, t.root);
							if (p == null && onlyIfPresent)
								break;
							V pv = (p == null) ? null : p.val;
							if ((val = mf.apply(k, pv)) != null) {
								if (p != null)
									p.val = val;
								else {
									len = 2;
									delta = 1;
									t.putTreeNode(h, k, val);
								}
							}
							else if (p != null) {
								delta = -1;
								t.deleteTreeNode(p);
							}
						}
					}
					finally {
						t.release(0);
					}
					if (len != 0)
						break;
				}
				else
					tab = (Node<V>[]) fk;
			}
			else {
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						len = 1;
						for (Node<V> e = f, pred = null;; ++len) {
							Object ek;
							V ev;
							if (e.hash == h
											&& (ev = e.val) != null
											&& ((ek = e.key) == k || k.equals(ek))) {
								val = mf.apply(k, ev);
								if (val != null)
									e.val = val;
								else {
									delta = -1;
									Node<V> en = e.next;
									if (pred != null)
										pred.next = en;
									else
										setTabAt(tab, i, en);
								}
								break;
							}
							pred = e;
							if ((e = e.next) == null) {
								if (!onlyIfPresent
												&& (val = mf.apply(k, null)) != null) {
									pred.next = new Node<V>(h, k, val, null);
									delta = 1;
									if (len >= TREE_THRESHOLD)
										replaceWithTreeBin(tab, i, k);
								}
								break;
							}
						}
					}
				}
				if (len != 0)
					break;
			}
		}
		if (delta != 0)
			addCount((long) delta, len);
		return val;
	}

	/**
	 * Implementation for merge
	 */
	@SuppressWarnings("unchecked")
	private final V internalMerge(K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
		if (k == null || v == null || mf == null)
			throw new NullPointerException();
		int h = spread(k.hashCode());
		V val = null;
		int delta = 0;
		int len = 0;
		for (Node<V>[] tab = table;;) {
			int i;
			Node<V> f;
			Object fk;
			V fv;
			if (tab == null)
				tab = initTable();
			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
				if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
					delta = 1;
					val = v;
					break;
				}
			}
			else if (f.hash < 0) {
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							len = 1;
							TreeNode<V> p = t.getTreeNode(h, k, t.root);
							val = (p == null) ? v : mf.apply(p.val, v);
							if (val != null) {
								if (p != null)
									p.val = val;
								else {
									len = 2;
									delta = 1;
									t.putTreeNode(h, k, val);
								}
							}
							else if (p != null) {
								delta = -1;
								t.deleteTreeNode(p);
							}
						}
					}
					finally {
						t.release(0);
					}
					if (len != 0)
						break;
				}
				else
					tab = (Node<V>[]) fk;
			}
			else {
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						len = 1;
						for (Node<V> e = f, pred = null;; ++len) {
							Object ek;
							V ev;
							if (e.hash == h
											&& (ev = e.val) != null
											&& ((ek = e.key) == k || k.equals(ek))) {
								val = mf.apply(ev, v);
								if (val != null)
									e.val = val;
								else {
									delta = -1;
									Node<V> en = e.next;
									if (pred != null)
										pred.next = en;
									else
										setTabAt(tab, i, en);
								}
								break;
							}
							pred = e;
							if ((e = e.next) == null) {
								val = v;
								pred.next = new Node<V>(h, k, val, null);
								delta = 1;
								if (len >= TREE_THRESHOLD)
									replaceWithTreeBin(tab, i, k);
								break;
							}
						}
					}
				}
				if (len != 0)
					break;
			}
		}
		if (delta != 0)
			addCount((long) delta, len);
		return val;
	}

	/**
	 * Implementation for putAll
	 */
	@SuppressWarnings("unchecked")
	private final void internalPutAll(Map<? extends K, ? extends V> m) {
		tryPresize(m.size());
		long delta = 0L;     // number of uncommitted additions
		boolean npe = false; // to throw exception on exit for nulls
		try {                // to clean up counts on other exceptions
			for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
				Object k;
				V v;
				if (entry == null || (k = entry.getKey()) == null
								|| (v = entry.getValue()) == null) {
					npe = true;
					break;
				}
				int h = spread(k.hashCode());
				for (Node<V>[] tab = table;;) {
					int i;
					Node<V> f;
					int fh;
					Object fk;
					if (tab == null)
						tab = initTable();
					else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
						if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
							++delta;
							break;
						}
					}
					else if ((fh = f.hash) < 0) {
						if ((fk = f.key) instanceof TreeBin) {
							TreeBin<V> t = (TreeBin<V>) fk;
							boolean validated = false;
							t.acquire(0);
							try {
								if (tabAt(tab, i) == f) {
									validated = true;
									TreeNode<V> p = t.getTreeNode(h, k, t.root);
									if (p != null)
										p.val = v;
									else {
										t.putTreeNode(h, k, v);
										++delta;
									}
								}
							}
							finally {
								t.release(0);
							}
							if (validated)
								break;
						}
						else
							tab = (Node<V>[]) fk;
					}
					else {
						int len = 0;
						synchronized (f) {
							if (tabAt(tab, i) == f) {
								len = 1;
								for (Node<V> e = f;; ++len) {
									Object ek;
									V ev;
									if (e.hash == h
													&& (ev = e.val) != null
													&& ((ek = e.key) == k || k.equals(ek))) {
										e.val = v;
										break;
									}
									Node<V> last = e;
									if ((e = e.next) == null) {
										++delta;
										last.next = new Node<V>(h, k, v, null);
										if (len >= TREE_THRESHOLD)
											replaceWithTreeBin(tab, i, k);
										break;
									}
								}
							}
						}
						if (len != 0) {
							if (len > 1) {
								addCount(delta, len);
								delta = 0L;
							}
							break;
						}
					}
				}
			}
		}
		finally {
			if (delta != 0L)
				addCount(delta, 2);
		}
		if (npe)
			throw new NullPointerException();
	}

	/**
	 * Implementation for clear. Steps through each bin, removing all nodes.
	 */
	@SuppressWarnings("unchecked")
	private final void internalClear() {
		long delta = 0L; // negative number of deletions
		int i = 0;
		Node<V>[] tab = table;
		while (tab != null && i < tab.length) {
			Node<V> f = tabAt(tab, i);
			if (f == null)
				++i;
			else if (f.hash < 0) {
				Object fk;
				if ((fk = f.key) instanceof TreeBin) {
					TreeBin<V> t = (TreeBin<V>) fk;
					t.acquire(0);
					try {
						if (tabAt(tab, i) == f) {
							for (Node<V> p = t.first; p != null; p = p.next) {
								if (p.val != null) { // (currently always true)
									p.val = null;
									--delta;
								}
							}
							t.first = null;
							t.root = null;
							++i;
						}
					}
					finally {
						t.release(0);
					}
				}
				else
					tab = (Node<V>[]) fk;
			}
			else {
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						for (Node<V> e = f; e != null; e = e.next) {
							if (e.val != null) {  // (currently always true)
								e.val = null;
								--delta;
							}
						}
						setTabAt(tab, i, null);
						++i;
					}
				}
			}
		}
		if (delta != 0L)
			addCount(delta, -1);
	}

	/* ---------------- Table Initialization and Resizing -------------- */
	/**
	 * Returns a power of two table size for the given desired capacity. See Hackers Delight, sec 3.2
	 */
	private static final int tableSizeFor(int c) {
		int n = c - 1;
		n |= n >>> 1;
		n |= n >>> 2;
		n |= n >>> 4;
		n |= n >>> 8;
		n |= n >>> 16;
		return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
	}

	/**
	 * Initializes table, using the size recorded in sizeCtl.
	 */
	@SuppressWarnings("unchecked")
	private final Node<V>[] initTable() {
		Node<V>[] tab;
		int sc;
		while ((tab = table) == null) {
			if ((sc = sizeCtl) < 0)
				Thread.yield(); // lost initialization race; just spin
			else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
				try {
					if ((tab = table) == null) {
						int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
						@SuppressWarnings("rawtypes")
						Node[] tb = new Node[n];
						table = tab = (Node<V>[]) tb;
						sc = n - (n >>> 2);
					}
				}
				finally {
					sizeCtl = sc;
				}
				break;
			}
		}
		return tab;
	}

	/**
	 * Adds to count, and if table is too small and not already resizing, initiates transfer. If already resizing, helps perform transfer if
	 * work is available. Rechecks occupancy after a transfer to see if another resize is already needed because resizings are lagging
	 * additions.
	 *
	 * @param x the count to add
	 * @param check if <0, don't check resize, if <= 1 only check if uncontended
	 */
	private final void addCount(long x, int check) {
		CounterCell[] as;
		long b, s;
		if ((as = counterCells) != null
						|| !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
			CounterHashCode hc;
			CounterCell a;
			long v;
			int m;
			boolean uncontended = true;
			if ((hc = threadCounterHashCode.get()) == null
							|| as == null || (m = as.length - 1) < 0
							|| (a = as[m & hc.code]) == null
							|| !(uncontended =
							U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
				fullAddCount(x, hc, uncontended);
				return;
			}
			if (check <= 1)
				return;
			s = sumCount();
		}
		if (check >= 0) {
			Node<V>[] tab, nt;
			int sc;
			while (s >= (long) (sc = sizeCtl) && (tab = table) != null
							&& tab.length < MAXIMUM_CAPACITY) {
				if (sc < 0) {
					if (sc == -1 || transferIndex <= transferOrigin
									|| (nt = nextTable) == null)
						break;
					if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
						transfer(tab, nt);
				}
				else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
					transfer(tab, null);
				s = sumCount();
			}
		}
	}

	/**
	 * Tries to presize table to accommodate the given number of elements.
	 *
	 * @param size number of elements (doesn't need to be perfectly accurate)
	 */
	@SuppressWarnings("unchecked")
	private final void tryPresize(int size) {
		int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY
						: tableSizeFor(size + (size >>> 1) + 1);
		int sc;
		while ((sc = sizeCtl) >= 0) {
			Node<V>[] tab = table;
			int n;
			if (tab == null || (n = tab.length) == 0) {
				n = (sc > c) ? sc : c;
				if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
					try {
						if (table == tab) {
							@SuppressWarnings("rawtypes")
							Node[] tb = new Node[n];
							table = (Node<V>[]) tb;
							sc = n - (n >>> 2);
						}
					}
					finally {
						sizeCtl = sc;
					}
				}
			}
			else if (c <= sc || n >= MAXIMUM_CAPACITY)
				break;
			else if (tab == table
							&& U.compareAndSwapInt(this, SIZECTL, sc, -2))
				transfer(tab, null);
		}
	}

	/**
	 * Moves and/or copies the nodes in each bin to new table. See above for explanation.
	 */
	@SuppressWarnings("unchecked")
	private final void transfer(Node<V>[] tab, Node<V>[] nextTab) {
		int n = tab.length, stride;
		if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
			stride = MIN_TRANSFER_STRIDE; // subdivide range
		if (nextTab == null) {            // initiating
			try {
				@SuppressWarnings("rawtypes")
				Node[] tb = new Node[n << 1];
				nextTab = (Node<V>[]) tb;
			}
			catch (Throwable ex) {      // try to cope with OOME
				sizeCtl = Integer.MAX_VALUE;
				return;
			}
			nextTable = nextTab;
			transferOrigin = n;
			transferIndex = n;
			Node<V> rev = new Node<V>(MOVED, tab, null, null);
			for (int k = n; k > 0;) {    // progressively reveal ready slots
				int nextk = (k > stride) ? k - stride : 0;
				for (int m = nextk; m < k; ++m)
					nextTab[m] = rev;
				for (int m = n + nextk; m < n + k; ++m)
					nextTab[m] = rev;
				U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
			}
		}
		int nextn = nextTab.length;
		Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
		boolean advance = true;
		for (int i = 0, bound = 0;;) {
			int nextIndex, nextBound;
			Node<V> f;
			Object fk;
			while (advance) {
				if (--i >= bound)
					advance = false;
				else if ((nextIndex = transferIndex) <= transferOrigin) {
					i = -1;
					advance = false;
				}
				else if (U.compareAndSwapInt(this, TRANSFERINDEX, nextIndex,
								nextBound = (nextIndex > stride
								? nextIndex - stride : 0))) {
					bound = nextBound;
					i = nextIndex - 1;
					advance = false;
				}
			}
			if (i < 0 || i >= n || i + n >= nextn) {
				for (int sc;;) {
					if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
						if (sc == -1) {
							nextTable = null;
							table = nextTab;
							sizeCtl = (n << 1) - (n >>> 1);
						}
						return;
					}
				}
			}
			else if ((f = tabAt(tab, i)) == null) {
				if (casTabAt(tab, i, null, fwd)) {
					setTabAt(nextTab, i, null);
					setTabAt(nextTab, i + n, null);
					advance = true;
				}
			}
			else if (f.hash >= 0) {
				synchronized (f) {
					if (tabAt(tab, i) == f) {
						int runBit = f.hash & n;
						Node<V> lastRun = f, lo = null, hi = null;
						for (Node<V> p = f.next; p != null; p = p.next) {
							int b = p.hash & n;
							if (b != runBit) {
								runBit = b;
								lastRun = p;
							}
						}
						if (runBit == 0)
							lo = lastRun;
						else
							hi = lastRun;
						for (Node<V> p = f; p != lastRun; p = p.next) {
							int ph = p.hash;
							Object pk = p.key;
							V pv = p.val;
							if ((ph & n) == 0)
								lo = new Node<V>(ph, pk, pv, lo);
							else
								hi = new Node<V>(ph, pk, pv, hi);
						}
						setTabAt(nextTab, i, lo);
						setTabAt(nextTab, i + n, hi);
						setTabAt(tab, i, fwd);
						advance = true;
					}
				}
			}
			else if ((fk = f.key) instanceof TreeBin) {
				TreeBin<V> t = (TreeBin<V>) fk;
				t.acquire(0);
				try {
					if (tabAt(tab, i) == f) {
						TreeBin<V> lt = new TreeBin<V>();
						TreeBin<V> ht = new TreeBin<V>();
						int lc = 0, hc = 0;
						for (Node<V> e = t.first; e != null; e = e.next) {
							int h = e.hash;
							Object k = e.key;
							V v = e.val;
							if ((h & n) == 0) {
								++lc;
								lt.putTreeNode(h, k, v);
							}
							else {
								++hc;
								ht.putTreeNode(h, k, v);
							}
						}
						Node<V> ln, hn; // throw away trees if too small
						if (lc < TREE_THRESHOLD) {
							ln = null;
							for (Node<V> p = lt.first; p != null; p = p.next)
								ln = new Node<V>(p.hash, p.key, p.val, ln);
						}
						else
							ln = new Node<V>(MOVED, lt, null, null);
						setTabAt(nextTab, i, ln);
						if (hc < TREE_THRESHOLD) {
							hn = null;
							for (Node<V> p = ht.first; p != null; p = p.next)
								hn = new Node<V>(p.hash, p.key, p.val, hn);
						}
						else
							hn = new Node<V>(MOVED, ht, null, null);
						setTabAt(nextTab, i + n, hn);
						setTabAt(tab, i, fwd);
						advance = true;
					}
				}
				finally {
					t.release(0);
				}
			}
			else
				advance = true; // already processed
		}
	}

	/* ---------------- Counter support -------------- */
	final long sumCount() {
		CounterCell[] as = counterCells;
		CounterCell a;
		long sum = baseCount;
		if (as != null) {
			for (int i = 0; i < as.length; ++i) {
				if ((a = as[i]) != null)
					sum += a.value;
			}
		}
		return sum;
	}

	// See LongAdder version for explanation
	private final void fullAddCount(long x, CounterHashCode hc,
					boolean wasUncontended) {
		int h;
		if (hc == null) {
			hc = new CounterHashCode();
			int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
			h = hc.code = (s == 0) ? 1 : s; // Avoid zero
			threadCounterHashCode.set(hc);
		}
		else
			h = hc.code;
		boolean collide = false;                // True if last slot nonempty
		for (;;) {
			CounterCell[] as;
			CounterCell a;
			int n;
			long v;
			if ((as = counterCells) != null && (n = as.length) > 0) {
				if ((a = as[(n - 1) & h]) == null) {
					if (counterBusy == 0) {            // Try to attach new Cell
						CounterCell r = new CounterCell(x); // Optimistic create
						if (counterBusy == 0
										&& U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
							boolean created = false;
							try {               // Recheck under lock
								CounterCell[] rs;
								int m, j;
								if ((rs = counterCells) != null
												&& (m = rs.length) > 0
												&& rs[j = (m - 1) & h] == null) {
									rs[j] = r;
									created = true;
								}
							}
							finally {
								counterBusy = 0;
							}
							if (created)
								break;
							continue;           // Slot is now non-empty
						}
					}
					collide = false;
				}
				else if (!wasUncontended)       // CAS already known to fail
					wasUncontended = true;      // Continue after rehash
				else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
					break;
				else if (counterCells != as || n >= NCPU)
					collide = false;            // At max size or stale
				else if (!collide)
					collide = true;
				else if (counterBusy == 0
								&& U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
					try {
						if (counterCells == as) {// Expand table unless stale
							CounterCell[] rs = new CounterCell[n << 1];
							for (int i = 0; i < n; ++i)
								rs[i] = as[i];
							counterCells = rs;
						}
					}
					finally {
						counterBusy = 0;
					}
					collide = false;
					continue;                   // Retry with expanded table
				}
				h ^= h << 13;                   // Rehash
				h ^= h >>> 17;
				h ^= h << 5;
			}
			else if (counterBusy == 0 && counterCells == as
							&& U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
				boolean init = false;
				try {                           // Initialize table
					if (counterCells == as) {
						CounterCell[] rs = new CounterCell[2];
						rs[h & 1] = new CounterCell(x);
						counterCells = rs;
						init = true;
					}
				}
				finally {
					counterBusy = 0;
				}
				if (init)
					break;
			}
			else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
				break;                          // Fall back on using base
		}
		hc.code = h;                            // Record index for next time
	}

	/* ----------------Table Traversal -------------- */
	/**
	 * Encapsulates traversal for methods such as containsValue; also serves as a base class for other iterators and bulk tasks.
	 *
	 * At each step, the iterator snapshots the key ("nextKey") and value ("nextVal") of a valid node (i.e., one that, at point of snapshot,
	 * has a non-null user value). Because val fields can change (including to null, indicating deletion), field nextVal might not be accurate
	 * at point of use, but still maintains the weak consistency property of holding a value that was once valid. To support iterator.remove,
	 * the nextKey field is not updated (nulled out) when the iterator cannot advance.
	 *
	 * Internal traversals directly access these fields, as in: {@code while (it.advance() != null) { process(it.nextKey); }}
	 *
	 * Exported iterators must track whether the iterator has advanced (in hasNext vs next) (by setting/checking/nulling field nextVal), and
	 * then extract key, value, or key-value pairs as return values of next().
	 *
	 * The iterator visits once each still-valid node that was reachable upon iterator construction. It might miss some that were added to a
	 * bin after the bin was visited, which is OK wrt consistency guarantees. Maintaining this property in the face of possible ongoing
	 * resizes requires a fair amount of bookkeeping state that is difficult to optimize away amidst volatile accesses. Even so, traversal
	 * maintains reasonable throughput.
	 *
	 * Normally, iteration proceeds bin-by-bin traversing lists. However, if the table has been resized, then all future steps must traverse
	 * both the bin at the current index as well as at (index + baseSize); and so on for further resizings. To paranoically cope with
	 * potential sharing by users of iterators across threads, iteration terminates if a bounds checks fails for a table read.
	 *
	 * This class extends CountedCompleter to streamline parallel iteration in bulk operations. This adds only a few fields of space overhead,
	 * which is small enough in cases where it is not needed to not worry about it. Because CountedCompleter is Serializable, but iterators
	 * need not be, we need to add warning suppressions.
	 */
	@SuppressWarnings("serial")
	static class Traverser<K, V, R>
					extends CountedCompleter<R> {

		final ConcurrentHashMapV8<K, V> map;
		Node<V> next;        // the next entry to use
		Object nextKey;      // cached key field of next
		V nextVal;           // cached val field of next
		Node<V>[] tab;       // current table; updated if resized
		int index;           // index of bin to use next
		int baseIndex;       // current index of initial table
		int baseLimit;       // index bound for initial table
		int baseSize;        // initial table size
		int batch;           // split control

		/**
		 * Creates iterator for all entries in the table.
		 */
		Traverser(ConcurrentHashMapV8<K, V> map) {
			this.map = map;
		}

		/**
		 * Creates iterator for split() methods and task constructors
		 */
		Traverser(ConcurrentHashMapV8<K, V> map, Traverser<K, V, ?> it, int batch) {
			super(it);
			this.batch = batch;
			if ((this.map = map) != null && it != null) { // split parent
				Node<V>[] t;
				if ((t = it.tab) == null
								&& (t = it.tab = map.table) != null)
					it.baseLimit = it.baseSize = t.length;
				this.tab = t;
				this.baseSize = it.baseSize;
				int hi = this.baseLimit = it.baseLimit;
				it.baseLimit = this.index = this.baseIndex =
								(hi + it.baseIndex + 1) >>> 1;
			}
		}

		/**
		 * Advances next; returns nextVal or null if terminated. See above for explanation.
		 */
		@SuppressWarnings("unchecked")
		final V advance() {
			Node<V> e = next;
			V ev = null;
			outer:
			do {
				if (e != null)                  // advance past used/skipped node
					e = e.next;
				while (e == null) {             // get to next non-null bin
					ConcurrentHashMapV8<K, V> m;
					Node<V>[] t;
					int b, i, n;
					Object ek; //  must use locals
					if ((t = tab) != null)
						n = t.length;
					else if ((m = map) != null && (t = tab = m.table) != null)
						n = baseLimit = baseSize = t.length;
					else
						break outer;
					if ((b = baseIndex) >= baseLimit
									|| (i = index) < 0 || i >= n)
						break outer;
					if ((e = tabAt(t, i)) != null && e.hash < 0) {
						if ((ek = e.key) instanceof TreeBin)
							e = ((TreeBin<V>) ek).first;
						else {
							tab = (Node<V>[]) ek;
							continue;           // restarts due to null val
						}
					}                           // visit upper slots if present
					index = (i += baseSize) < n ? i : (baseIndex = b + 1);
				}
				nextKey = e.key;
			}
			while ((ev = e.val) == null);    // skip deleted or special nodes
			next = e;
			return nextVal = ev;
		}

		public final void remove() {
			Object k = nextKey;
			if (k == null && (advance() == null || (k = nextKey) == null))
				throw new IllegalStateException();
			map.internalReplace(k, null, null);
		}

		public final boolean hasNext() {
			return nextVal != null || advance() != null;
		}

		public final boolean hasMoreElements() {
			return hasNext();
		}

		public void compute() {
		} // default no-op CountedCompleter body

		/**
		 * Returns a batch value > 0 if this task should (and must) be split, if so, adding to pending count, and in any case updating batch
		 * value. The initial batch value is approx exp2 of the number of times (minus one) to split task by two before executing leaf action.
		 * This value is faster to compute and more convenient to use as a guide to splitting than is the depth, since it is used while dividing
		 * by two anyway.
		 */
		final int preSplit() {
			ConcurrentHashMapV8<K, V> m;
			int b;
			Node<V>[] t;
			ForkJoinPool pool;
			if ((b = batch) < 0 && (m = map) != null) { // force initialization
				if ((t = tab) == null && (t = tab = m.table) != null)
					baseLimit = baseSize = t.length;
				if (t != null) {
					long n = m.sumCount();
					int par = ((pool = getPool()) == null)
									? ForkJoinPool.getCommonPoolParallelism()
									: pool.getParallelism();
					int sp = par << 3; // slack of 8
					b = (n <= 0L) ? 0 : (n < (long) sp) ? (int) n : sp;
				}
			}
			b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
			if ((batch = b) > 0)
				addToPendingCount(1);
			return b;
		}
	}

	/* ---------------- Public operations -------------- */
	/**
	 * Creates a new, empty map with the default initial table size (16).
	 */
	public ConcurrentHashMapV8() {
	}

	/**
	 * Creates a new, empty map with an initial table size accommodating the specified number of elements without the need to dynamically
	 * resize.
	 *
	 * @param initialCapacity The implementation performs internal sizing to accommodate this many elements.
	 * @throws IllegalArgumentException if the initial capacity of elements is negative
	 */
	public ConcurrentHashMapV8(int initialCapacity) {
		if (initialCapacity < 0)
			throw new IllegalArgumentException();
		int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1))
						? MAXIMUM_CAPACITY
						: tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
		this.sizeCtl = cap;
	}

	/**
	 * Creates a new map with the same mappings as the given map.
	 *
	 * @param m the map
	 */
	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
		this.sizeCtl = DEFAULT_CAPACITY;
		internalPutAll(m);
	}

	/**
	 * Creates a new, empty map with an initial table size based on the given number of elements ({@code initialCapacity}) and initial table
	 * density ({@code loadFactor}).
	 *
	 * @param initialCapacity the initial capacity. The implementation performs internal sizing to accommodate this many elements, given the
	 * specified load factor.
	 * @param loadFactor the load factor (table density) for establishing the initial table size
	 * @throws IllegalArgumentException if the initial capacity of elements is negative or the load factor is nonpositive
	 *
	 * @since 1.6
	 */
	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
		this(initialCapacity, loadFactor, 1);
	}

	/**
	 * Creates a new, empty map with an initial table size based on the given number of elements ({@code initialCapacity}), table density
	 * ({@code loadFactor}), and number of concurrently updating threads ({@code concurrencyLevel}).
	 *
	 * @param initialCapacity the initial capacity. The implementation performs internal sizing to accommodate this many elements, given the
	 * specified load factor.
	 * @param loadFactor the load factor (table density) for establishing the initial table size
	 * @param concurrencyLevel the estimated number of concurrently updating threads. The implementation may use this value as a sizing hint.
	 * @throws IllegalArgumentException if the initial capacity is negative or the load factor or concurrencyLevel are nonpositive
	 */
	public ConcurrentHashMapV8(int initialCapacity,
					float loadFactor, int concurrencyLevel) {
		if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
			throw new IllegalArgumentException();
		if (initialCapacity < concurrencyLevel)   // Use at least as many bins
			initialCapacity = concurrencyLevel;   // as estimated threads
		long size = (long) (1.0 + (long) initialCapacity / loadFactor);
		int cap = (size >= (long) MAXIMUM_CAPACITY)
						? MAXIMUM_CAPACITY : tableSizeFor((int) size);
		this.sizeCtl = cap;
	}

	/**
	 * Creates a new {@link Set} backed by a ConcurrentHashMapV8 from the given type to {@code Boolean.TRUE}.
	 *
	 * @return the new set
	 */
	public static <K> KeySetView<K, Boolean> newKeySet() {
		return new KeySetView<K, Boolean>(new ConcurrentHashMapV8<K, Boolean>(),
						Boolean.TRUE);
	}

	/**
	 * Creates a new {@link Set} backed by a ConcurrentHashMapV8 from the given type to {@code Boolean.TRUE}.
	 *
	 * @param initialCapacity The implementation performs internal sizing to accommodate this many elements.
	 * @throws IllegalArgumentException if the initial capacity of elements is negative
	 * @return the new set
	 */
	public static <K> KeySetView<K, Boolean> newKeySet(int initialCapacity) {
		return new KeySetView<K, Boolean>(new ConcurrentHashMapV8<K, Boolean>(initialCapacity), Boolean.TRUE);
	}

	/**
	 * {@inheritDoc}
	 */
	public boolean isEmpty() {
		return sumCount() <= 0L; // ignore transient negative values
	}

	/**
	 * {@inheritDoc}
	 */
	public int size() {
		long n = sumCount();
		return ((n < 0L) ? 0
						: (n > (long) Integer.MAX_VALUE) ? Integer.MAX_VALUE
						: (int) n);
	}

	/**
	 * Returns the number of mappings. This method should be used instead of {@link #size} because a ConcurrentHashMapV8 may contain more
	 * mappings than can be represented as an int. The value returned is an estimate; the actual count may differ if there are concurrent
	 * insertions or removals.
	 *
	 * @return the number of mappings
	 */
	public long mappingCount() {
		long n = sumCount();
		return (n < 0L) ? 0L : n; // ignore transient negative values
	}

	/**
	 * Returns the value to which the specified key is mapped, or {@code null} if this map contains no mapping for the key.
	 *
	 * <p>More formally, if this map contains a mapping from a key {@code k} to a value {@code v} such that {@code key.equals(k)}, then this
	 * method returns {@code v}; otherwise it returns {@code null}. (There can be at most one such mapping.)
	 *
	 * @throws NullPointerException if the specified key is null
	 */
	public V get(Object key) {
		return internalGet(key);
	}

	/**
	 * Returns the value to which the specified key is mapped, or the given defaultValue if this map contains no mapping for the key.
	 *
	 * @param key the key
	 * @param defaultValue the value to return if this map contains no mapping for the given key
	 * @return the mapping for the key, if present; else the defaultValue
	 * @throws NullPointerException if the specified key is null
	 */
	public V getValueOrDefault(Object key, V defaultValue) {
		V v;
		return (v = internalGet(key)) == null ? defaultValue : v;
	}

	/**
	 * Tests if the specified object is a key in this table.
	 *
	 * @param key possible key
	 * @return {@code true} if and only if the specified object is a key in this table, as determined by the {@code equals} method;
	 * {@code false} otherwise
	 * @throws NullPointerException if the specified key is null
	 */
	public boolean containsKey(Object key) {
		return internalGet(key) != null;
	}

	/**
	 * Returns {@code true} if this map maps one or more keys to the specified value. Note: This method may require a full traversal of the
	 * map, and is much slower than method {@code containsKey}.
	 *
	 * @param value value whose presence in this map is to be tested
	 * @return {@code true} if this map maps one or more keys to the specified value
	 * @throws NullPointerException if the specified value is null
	 */
	public boolean containsValue(Object value) {
		if (value == null)
			throw new NullPointerException();
		V v;
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		while ((v = it.advance()) != null) {
			if (v == value || value.equals(v))
				return true;
		}
		return false;
	}

	/**
	 * Legacy method testing if some key maps into the specified value in this table. This method is identical in functionality to
	 * {@link #containsValue}, and exists solely to ensure full compatibility with class {@link java.util.Hashtable}, which supported this
	 * method prior to introduction of the Java Collections framework.
	 *
	 * @param value a value to search for
	 * @return {@code true} if and only if some key maps to the {@code value} argument in this table as determined by the {@code equals}
	 * method; {@code false} otherwise
	 * @throws NullPointerException if the specified value is null
	 */
	@Deprecated
	public boolean contains(Object value) {
		return containsValue(value);
	}

	/**
	 * Maps the specified key to the specified value in this table. Neither the key nor the value can be null.
	 *
	 * <p>The value can be retrieved by calling the {@code get} method with a key that is equal to the original key.
	 *
	 * @param key key with which the specified value is to be associated
	 * @param value value to be associated with the specified key
	 * @return the previous value associated with {@code key}, or {@code null} if there was no mapping for {@code key}
	 * @throws NullPointerException if the specified key or value is null
	 */
	public V put(K key, V value) {
		return internalPut(key, value, false);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return the previous value associated with the specified key, or {@code null} if there was no mapping for the key
	 * @throws NullPointerException if the specified key or value is null
	 */
	public V putIfAbsent(K key, V value) {
		return internalPut(key, value, true);
	}

	/**
	 * Copies all of the mappings from the specified map to this one. These mappings replace any mappings that this map had for any of the
	 * keys currently in the specified map.
	 *
	 * @param m mappings to be stored in this map
	 */
	public void putAll(Map<? extends K, ? extends V> m) {
		internalPutAll(m);
	}

	/**
	 * If the specified key is not already associated with a value, computes its value using the given mappingFunction and enters it into the
	 * map unless null. This is equivalent to
	 * <pre> {@code
	 * if (map.containsKey(key))
	 *   return map.get(key);
	 * value = mappingFunction.apply(key);
	 * if (value != null)
	 *   map.put(key, value);
	 * return value;}</pre>
	 *
	 * except that the action is performed atomically. If the function returns {@code null} no mapping is recorded. If the function itself
	 * throws an (unchecked) exception, the exception is rethrown to its caller, and no mapping is recorded. Some attempted update operations
	 * on this map by other threads may be blocked while computation is in progress, so the computation should be short and simple, and must
	 * not attempt to update any other mappings of this Map. The most appropriate usage is to construct a new object serving as an initial
	 * mapped value, or memoized result, as in:
	 *
	 * <pre> {@code
	 * map.computeIfAbsent(key, new Fun<K,V>() {
	 *   public V map(K k) { return new Value(f(k)); }});}</pre>
	 *
	 * @param key key with which the specified value is to be associated
	 * @param mappingFunction the function to compute a value
	 * @return the current (existing or computed) value associated with the specified key, or null if the computed value is null
	 * @throws NullPointerException if the specified key or mappingFunction is null
	 * @throws IllegalStateException if the computation detectably attempts a recursive update to this map that would otherwise never complete
	 * @throws RuntimeException or Error if the mappingFunction does so, in which case the mapping is left unestablished
	 */
	public V computeIfAbsent(K key, Fun<? super K, ? extends V> mappingFunction) {
		return internalComputeIfAbsent(key, mappingFunction);
	}

	/**
	 * If the given key is present, computes a new mapping value given a key and its current mapped value. This is equivalent to
	 * <pre> {@code
	 *   if (map.containsKey(key)) {
	 *     value = remappingFunction.apply(key, map.get(key));
	 *     if (value != null)
	 *       map.put(key, value);
	 *     else
	 *       map.remove(key);
	 *   }
	 * }</pre>
	 *
	 * except that the action is performed atomically. If the function returns {@code null}, the mapping is removed. If the function itself
	 * throws an (unchecked) exception, the exception is rethrown to its caller, and the current mapping is left unchanged. Some attempted
	 * update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and
	 * simple, and must not attempt to update any other mappings of this Map. For example, to either create or append new messages to a value
	 * mapping:
	 *
	 * @param key key with which the specified value is to be associated
	 * @param remappingFunction the function to compute a value
	 * @return the new value associated with the specified key, or null if none
	 * @throws NullPointerException if the specified key or remappingFunction is null
	 * @throws IllegalStateException if the computation detectably attempts a recursive update to this map that would otherwise never complete
	 * @throws RuntimeException or Error if the remappingFunction does so, in which case the mapping is unchanged
	 */
	public V computeIfPresent(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
		return internalCompute(key, true, remappingFunction);
	}

	/**
	 * Computes a new mapping value given a key and its current mapped value (or {@code null} if there is no current mapping). This is
	 * equivalent to
	 * <pre> {@code
	 *   value = remappingFunction.apply(key, map.get(key));
	 *   if (value != null)
	 *     map.put(key, value);
	 *   else
	 *     map.remove(key);
	 * }</pre>
	 *
	 * except that the action is performed atomically. If the function returns {@code null}, the mapping is removed. If the function itself
	 * throws an (unchecked) exception, the exception is rethrown to its caller, and the current mapping is left unchanged. Some attempted
	 * update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and
	 * simple, and must not attempt to update any other mappings of this Map. For example, to either create or append new messages to a value
	 * mapping:
	 *
	 * <pre> {@code
	 * Map<Key, String> map = ...;
	 * final String msg = ...;
	 * map.compute(key, new BiFun<Key, String, String>() {
	 *   public String apply(Key k, String v) {
	 *    return (v == null) ? msg : v + msg;});}}</pre>
	 *
	 * @param key key with which the specified value is to be associated
	 * @param remappingFunction the function to compute a value
	 * @return the new value associated with the specified key, or null if none
	 * @throws NullPointerException if the specified key or remappingFunction is null
	 * @throws IllegalStateException if the computation detectably attempts a recursive update to this map that would otherwise never complete
	 * @throws RuntimeException or Error if the remappingFunction does so, in which case the mapping is unchanged
	 */
	public V compute(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
		return internalCompute(key, false, remappingFunction);
	}

	/**
	 * If the specified key is not already associated with a value, associate it with the given value. Otherwise, replace the value with the
	 * results of the given remapping function. This is equivalent to:
	 * <pre> {@code
	 *   if (!map.containsKey(key))
	 *     map.put(value);
	 *   else {
	 *     newValue = remappingFunction.apply(map.get(key), value);
	 *     if (value != null)
	 *       map.put(key, value);
	 *     else
	 *       map.remove(key);
	 *   }
	 * }</pre> except that the action is performed atomically. If the function returns {@code null}, the mapping is removed. If the function
	 * itself throws an (unchecked) exception, the exception is rethrown to its caller, and the current mapping is left unchanged. Some
	 * attempted update operations on this map by other threads may be blocked while computation is in progress, so the computation should be
	 * short and simple, and must not attempt to update any other mappings of this Map.
	 */
	public V merge(K key, V value,
					BiFun<? super V, ? super V, ? extends V> remappingFunction) {
		return internalMerge(key, value, remappingFunction);
	}

	/**
	 * Removes the key (and its corresponding value) from this map. This method does nothing if the key is not in the map.
	 *
	 * @param key the key that needs to be removed
	 * @return the previous value associated with {@code key}, or {@code null} if there was no mapping for {@code key}
	 * @throws NullPointerException if the specified key is null
	 */
	public V remove(Object key) {
		return internalReplace(key, null, null);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @throws NullPointerException if the specified key is null
	 */
	public boolean remove(Object key, Object value) {
		return value != null && internalReplace(key, null, value) != null;
	}

	/**
	 * {@inheritDoc}
	 *
	 * @throws NullPointerException if any of the arguments are null
	 */
	public boolean replace(K key, V oldValue, V newValue) {
		if (key == null || oldValue == null || newValue == null)
			throw new NullPointerException();
		return internalReplace(key, newValue, oldValue) != null;
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return the previous value associated with the specified key, or {@code null} if there was no mapping for the key
	 * @throws NullPointerException if the specified key or value is null
	 */
	public V replace(K key, V value) {
		if (key == null || value == null)
			throw new NullPointerException();
		return internalReplace(key, value, null);
	}

	/**
	 * Removes all of the mappings from this map.
	 */
	public void clear() {
		internalClear();
	}

	/**
	 * Returns a {@link Set} view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the
	 * set, and vice-versa.
	 *
	 * @return the set view
	 */
	public KeySetView<K, V> keySet() {
		KeySetView<K, V> ks = keySet;
		return (ks != null) ? ks : (keySet = new KeySetView<K, V>(this, null));
	}

	/**
	 * Returns a {@link Set} view of the keys in this map, using the given common mapped value for any additions (i.e., {@link
	 * Collection#add} and {@link Collection#addAll}). This is of course only appropriate if it is acceptable to use the same value for all
	 * additions from this view.
	 *
	 * @param mappedValue the mapped value to use for any additions
	 * @return the set view
	 * @throws NullPointerException if the mappedValue is null
	 */
	public KeySetView<K, V> keySet(V mappedValue) {
		if (mappedValue == null)
			throw new NullPointerException();
		return new KeySetView<K, V>(this, mappedValue);
	}

	/**
	 * Returns a {@link Collection} view of the values contained in this map. The collection is backed by the map, so changes to the map are
	 * reflected in the collection, and vice-versa.
	 */
	public ValuesView<K, V> values() {
		ValuesView<K, V> vs = values;
		return (vs != null) ? vs : (values = new ValuesView<K, V>(this));
	}

	/**
	 * Returns a {@link Set} view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in
	 * the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via the {@code Iterator.remove}, {@code Set.remove},
	 * {@code removeAll}, {@code retainAll}, and {@code clear} operations. It does not support the {@code add} or {@code addAll} operations.
	 *
	 * <p>The view's {@code iterator} is a "weakly consistent" iterator that will never throw {@link ConcurrentModificationException}, and
	 * guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any
	 * modifications subsequent to construction.
	 */
	public Set<Map.Entry<K, V>> entrySet() {
		EntrySetView<K, V> es = entrySet;
		return (es != null) ? es : (entrySet = new EntrySetView<K, V>(this));
	}

	/**
	 * Returns an enumeration of the keys in this table.
	 *
	 * @return an enumeration of the keys in this table
	 * @see #keySet()
	 */
	public Enumeration<K> keys() {
		return new KeyIterator<K, V>(this);
	}

	/**
	 * Returns an enumeration of the values in this table.
	 *
	 * @return an enumeration of the values in this table
	 * @see #values()
	 */
	public Enumeration<V> elements() {
		return new ValueIterator<K, V>(this);
	}

	/**
	 * Returns a partitionable iterator of the keys in this map.
	 *
	 * @return a partitionable iterator of the keys in this map
	 */
	public Spliterator<K> keySpliterator() {
		return new KeyIterator<K, V>(this);
	}

	/**
	 * Returns a partitionable iterator of the values in this map.
	 *
	 * @return a partitionable iterator of the values in this map
	 */
	public Spliterator<V> valueSpliterator() {
		return new ValueIterator<K, V>(this);
	}

	/**
	 * Returns a partitionable iterator of the entries in this map.
	 *
	 * @return a partitionable iterator of the entries in this map
	 */
	public Spliterator<Map.Entry<K, V>> entrySpliterator() {
		return new EntryIterator<K, V>(this);
	}

	/**
	 * Returns the hash code value for this {@link Map}, i.e., the sum of, for each key-value pair in the map,
	 * {@code key.hashCode() ^ value.hashCode()}.
	 *
	 * @return the hash code value for this map
	 */
	public int hashCode() {
		int h = 0;
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		while ((v = it.advance()) != null) {
			h += it.nextKey.hashCode() ^ v.hashCode();
		}
		return h;
	}

	/**
	 * Returns a string representation of this map. The string representation consists of a list of key-value mappings (in no particular
	 * order) enclosed in braces ("{@code {}}"). Adjacent mappings are separated by the characters {@code ", "} (comma and space). Each
	 * key-value mapping is rendered as the key followed by an equals sign ("{@code =}") followed by the associated value.
	 *
	 * @return a string representation of this map
	 */
	public String toString() {
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		StringBuilder sb = new StringBuilder();
		sb.append('{');
		V v;
		if ((v = it.advance()) != null) {
			for (;;) {
				Object k = it.nextKey;
				sb.append(k == this ? "(this Map)" : k);
				sb.append('=');
				sb.append(v == this ? "(this Map)" : v);
				if ((v = it.advance()) == null)
					break;
				sb.append(',').append(' ');
			}
		}
		return sb.append('}').toString();
	}

	/**
	 * Compares the specified object with this map for equality. Returns {@code true} if the given object is a map with the same mappings as
	 * this map. This operation may return misleading results if either map is concurrently modified during execution of this method.
	 *
	 * @param o object to be compared for equality with this map
	 * @return {@code true} if the specified object is equal to this map
	 */
	public boolean equals(Object o) {
		if (o != this) {
			if (!(o instanceof Map))
				return false;
			Map<?, ?> m = (Map<?, ?>) o;
			Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
			V val;
			while ((val = it.advance()) != null) {
				Object v = m.get(it.nextKey);
				if (v == null || (v != val && !v.equals(val)))
					return false;
			}
			for (Map.Entry<?, ?> e : m.entrySet()) {
				Object mk, mv, v;
				if ((mk = e.getKey()) == null
								|| (mv = e.getValue()) == null
								|| (v = internalGet(mk)) == null
								|| (mv != v && !mv.equals(v)))
					return false;
			}
		}
		return true;
	}

	/* ----------------Iterators -------------- */
	@SuppressWarnings("serial")
	static final class KeyIterator<K, V>
					extends Traverser<K, V, Object>
					implements Spliterator<K>, Enumeration<K> {

		KeyIterator(ConcurrentHashMapV8<K, V> map) {
			super(map);
		}

		KeyIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
			super(map, it, -1);
		}

		public KeyIterator<K, V> split() {
			if (nextKey != null)
				throw new IllegalStateException();
			return new KeyIterator<K, V>(map, this);
		}

		@SuppressWarnings("unchecked")
		public final K next() {
			if (nextVal == null && advance() == null)
				throw new NoSuchElementException();
			Object k = nextKey;
			nextVal = null;
			return (K) k;
		}

		public final K nextElement() {
			return next();
		}
	}

	@SuppressWarnings("serial")
	static final class ValueIterator<K, V>
					extends Traverser<K, V, Object>
					implements Spliterator<V>, Enumeration<V> {

		ValueIterator(ConcurrentHashMapV8<K, V> map) {
			super(map);
		}

		ValueIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
			super(map, it, -1);
		}

		public ValueIterator<K, V> split() {
			if (nextKey != null)
				throw new IllegalStateException();
			return new ValueIterator<K, V>(map, this);
		}

		public final V next() {
			V v;
			if ((v = nextVal) == null && (v = advance()) == null)
				throw new NoSuchElementException();
			nextVal = null;
			return v;
		}

		public final V nextElement() {
			return next();
		}
	}

	@SuppressWarnings("serial")
	static final class EntryIterator<K, V>
					extends Traverser<K, V, Object>
					implements Spliterator<Map.Entry<K, V>> {

		EntryIterator(ConcurrentHashMapV8<K, V> map) {
			super(map);
		}

		EntryIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
			super(map, it, -1);
		}

		public EntryIterator<K, V> split() {
			if (nextKey != null)
				throw new IllegalStateException();
			return new EntryIterator<K, V>(map, this);
		}

		@SuppressWarnings("unchecked")
		public final Map.Entry<K, V> next() {
			V v;
			if ((v = nextVal) == null && (v = advance()) == null)
				throw new NoSuchElementException();
			Object k = nextKey;
			nextVal = null;
			return new MapEntry<K, V>((K) k, v, map);
		}
	}

	/**
	 * Exported Entry for iterators
	 */
	static final class MapEntry<K, V> implements Map.Entry<K, V> {

		final K key; // non-null
		V val;       // non-null
		final ConcurrentHashMapV8<K, V> map;

		MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
			this.key = key;
			this.val = val;
			this.map = map;
		}

		public final K getKey() {
			return key;
		}

		public final V getValue() {
			return val;
		}

		public final int hashCode() {
			return key.hashCode() ^ val.hashCode();
		}

		public final String toString() {
			return key + "=" + val;
		}

		public final boolean equals(Object o) {
			Object k, v;
			Map.Entry<?, ?> e;
			return ((o instanceof Map.Entry)
							&& (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
							&& (v = e.getValue()) != null
							&& (k == key || k.equals(key))
							&& (v == val || v.equals(val)));
		}

		/**
		 * Sets our entry's value and writes through to the map. The value to return is somewhat arbitrary here. Since we do not necessarily
		 * track asynchronous changes, the most recent "previous" value could be different from what we return (or could even have been removed
		 * in which case the put will re-establish). We do not and cannot guarantee more.
		 */
		public final V setValue(V value) {
			if (value == null)
				throw new NullPointerException();
			V v = val;
			val = value;
			map.put(key, value);
			return v;
		}
	}

	/**
	 * Returns exportable snapshot entry for the given key and value when write-through can't or shouldn't be used.
	 */
	static <K, V> AbstractMap.SimpleEntry<K, V> entryFor(K k, V v) {
		return new AbstractMap.SimpleEntry<K, V>(k, v);
	}

	/* ---------------- Serialization Support -------------- */
	/**
	 * Stripped-down version of helper class used in previous version, declared for the sake of serialization compatibility
	 */
	static class Segment<K, V> implements Serializable {

		private static final long serialVersionUID = 2249069246763182397L;
		final float loadFactor;

		Segment(float lf) {
			this.loadFactor = lf;
		}
	}

	/**
	 * Saves the state of the {@code ConcurrentHashMapV8} instance to a stream (i.e., serializes it).
	 *
	 * @param s the stream
	 * @serialData the key (Object) and value (Object) for each key-value mapping, followed by a null pair. The key-value mappings are emitted
	 * in no particular order.
	 */
	@SuppressWarnings("unchecked")
	private void writeObject(java.io.ObjectOutputStream s)
					throws java.io.IOException {
		if (segments == null) { // for serialization compatibility
			segments = (Segment<K, V>[]) new Segment<?, ?>[DEFAULT_CONCURRENCY_LEVEL];
			for (int i = 0; i < segments.length; ++i)
				segments[i] = new Segment<K, V>(LOAD_FACTOR);
		}
		s.defaultWriteObject();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		while ((v = it.advance()) != null) {
			s.writeObject(it.nextKey);
			s.writeObject(v);
		}
		s.writeObject(null);
		s.writeObject(null);
		segments = null; // throw away
	}

	/**
	 * Reconstitutes the instance from a stream (that is, deserializes it).
	 *
	 * @param s the stream
	 */
	@SuppressWarnings("unchecked")
	private void readObject(java.io.ObjectInputStream s)
					throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();
		this.segments = null; // unneeded

		// Create all nodes, then place in table once size is known
		long size = 0L;
		Node<V> p = null;
		for (;;) {
			K k = (K) s.readObject();
			V v = (V) s.readObject();
			if (k != null && v != null) {
				int h = spread(k.hashCode());
				p = new Node<V>(h, k, v, p);
				++size;
			}
			else
				break;
		}
		if (p != null) {
			boolean init = false;
			int n;
			if (size >= (long) (MAXIMUM_CAPACITY >>> 1))
				n = MAXIMUM_CAPACITY;
			else {
				int sz = (int) size;
				n = tableSizeFor(sz + (sz >>> 1) + 1);
			}
			int sc = sizeCtl;
			boolean collide = false;
			if (n > sc
							&& U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
				try {
					if (table == null) {
						init = true;
						@SuppressWarnings("rawtypes")
						Node[] rt = new Node[n];
						Node<V>[] tab = (Node<V>[]) rt;
						int mask = n - 1;
						while (p != null) {
							int j = p.hash & mask;
							Node<V> next = p.next;
							Node<V> q = p.next = tabAt(tab, j);
							setTabAt(tab, j, p);
							if (!collide && q != null && q.hash == p.hash)
								collide = true;
							p = next;
						}
						table = tab;
						addCount(size, -1);
						sc = n - (n >>> 2);
					}
				}
				finally {
					sizeCtl = sc;
				}
				if (collide) { // rescan and convert to TreeBins
					Node<V>[] tab = table;
					for (int i = 0; i < tab.length; ++i) {
						int c = 0;
						for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
							if (++c > TREE_THRESHOLD
											&& (e.key instanceof Comparable)) {
								replaceWithTreeBin(tab, i, e.key);
								break;
							}
						}
					}
				}
			}
			if (!init) { // Can only happen if unsafely published.
				while (p != null) {
					internalPut((K) p.key, p.val, false);
					p = p.next;
				}
			}
		}
	}

	// -------------------------------------------------------
	// Sams
	/**
	 * Interface describing a void action of one argument
	 */
	public interface Action<A> {

		void apply(A a);
	}

	/**
	 * Interface describing a void action of two arguments
	 */
	public interface BiAction<A, B> {

		void apply(A a, B b);
	}

	/**
	 * Interface describing a function of one argument
	 */
	public interface Fun<A, T> {

		T apply(A a);
	}

	/**
	 * Interface describing a function of two arguments
	 */
	public interface BiFun<A, B, T> {

		T apply(A a, B b);
	}

	/**
	 * Interface describing a function of no arguments
	 */
	public interface Generator<T> {

		T apply();
	}

	/**
	 * Interface describing a function mapping its argument to a double
	 */
	public interface ObjectToDouble<A> {

		double apply(A a);
	}

	/**
	 * Interface describing a function mapping its argument to a long
	 */
	public interface ObjectToLong<A> {

		long apply(A a);
	}

	/**
	 * Interface describing a function mapping its argument to an int
	 */
	public interface ObjectToInt<A> {

		int apply(A a);
	}

	/**
	 * Interface describing a function mapping two arguments to a double
	 */
	public interface ObjectByObjectToDouble<A, B> {

		double apply(A a, B b);
	}

	/**
	 * Interface describing a function mapping two arguments to a long
	 */
	public interface ObjectByObjectToLong<A, B> {

		long apply(A a, B b);
	}

	/**
	 * Interface describing a function mapping two arguments to an int
	 */
	public interface ObjectByObjectToInt<A, B> {

		int apply(A a, B b);
	}

	/**
	 * Interface describing a function mapping a double to a double
	 */
	public interface DoubleToDouble {

		double apply(double a);
	}

	/**
	 * Interface describing a function mapping a long to a long
	 */
	public interface LongToLong {

		long apply(long a);
	}

	/**
	 * Interface describing a function mapping an int to an int
	 */
	public interface IntToInt {

		int apply(int a);
	}

	/**
	 * Interface describing a function mapping two doubles to a double
	 */
	public interface DoubleByDoubleToDouble {

		double apply(double a, double b);
	}

	/**
	 * Interface describing a function mapping two longs to a long
	 */
	public interface LongByLongToLong {

		long apply(long a, long b);
	}

	/**
	 * Interface describing a function mapping two ints to an int
	 */
	public interface IntByIntToInt {

		int apply(int a, int b);
	}

	// -------------------------------------------------------
	// Sequential bulk operations
	/**
	 * Performs the given action for each (key, value).
	 *
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public void forEachSequentially(BiAction<K, V> action) {
		if (action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		while ((v = it.advance()) != null)
			action.apply((K) it.nextKey, v);
	}

	/**
	 * Performs the given action for each non-null transformation of each (key, value).
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public <U> void forEachSequentially(BiFun<? super K, ? super V, ? extends U> transformer,
					Action<U> action) {
		if (transformer == null || action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply((K) it.nextKey, v)) != null)
				action.apply(u);
		}
	}

	/**
	 * Returns a non-null result from applying the given search function on each (key, value), or null if none.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each (key, value), or null if none
	 */
	@SuppressWarnings("unchecked")
	public <U> U searchSequentially(BiFun<? super K, ? super V, ? extends U> searchFunction) {
		if (searchFunction == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = searchFunction.apply((K) it.nextKey, v)) != null)
				return u;
		}
		return null;
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, or
	 * null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	@SuppressWarnings("unchecked")
	public <U> U reduceSequentially(BiFun<? super K, ? super V, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U r = null, u;
		V v;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply((K) it.nextKey, v)) != null)
				r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	@SuppressWarnings("unchecked")
	public double reduceToDoubleSequentially(ObjectByObjectToDouble<? super K, ? super V> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		double r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	@SuppressWarnings("unchecked")
	public long reduceToLongSequentially(ObjectByObjectToLong<? super K, ? super V> transformer,
					long basis,
					LongByLongToLong reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		long r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	@SuppressWarnings("unchecked")
	public int reduceToIntSequentially(ObjectByObjectToInt<? super K, ? super V> transformer,
					int basis,
					IntByIntToInt reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		int r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
		return r;
	}

	/**
	 * Performs the given action for each key.
	 *
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public void forEachKeySequentially(Action<K> action) {
		if (action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		while (it.advance() != null)
			action.apply((K) it.nextKey);
	}

	/**
	 * Performs the given action for each non-null transformation of each key.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public <U> void forEachKeySequentially(Fun<? super K, ? extends U> transformer,
					Action<U> action) {
		if (transformer == null || action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U u;
		while (it.advance() != null) {
			if ((u = transformer.apply((K) it.nextKey)) != null)
				action.apply(u);
		}
		ForkJoinTasks.forEachKey(this, transformer, action).invoke();
	}

	/**
	 * Returns a non-null result from applying the given search function on each key, or null if none.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each key, or null if none
	 */
	@SuppressWarnings("unchecked")
	public <U> U searchKeysSequentially(Fun<? super K, ? extends U> searchFunction) {
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U u;
		while (it.advance() != null) {
			if ((u = searchFunction.apply((K) it.nextKey)) != null)
				return u;
		}
		return null;
	}

	/**
	 * Returns the result of accumulating all keys using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all keys using the given reducer to combine values, or null if none
	 */
	@SuppressWarnings("unchecked")
	public K reduceKeysSequentially(BiFun<? super K, ? super K, ? extends K> reducer) {
		if (reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		K r = null;
		while (it.advance() != null) {
			K u = (K) it.nextKey;
			r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	@SuppressWarnings("unchecked")
	public <U> U reduceKeysSequentially(Fun<? super K, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U r = null, u;
		while (it.advance() != null) {
			if ((u = transformer.apply((K) it.nextKey)) != null)
				r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	@SuppressWarnings("unchecked")
	public double reduceKeysToDoubleSequentially(ObjectToDouble<? super K> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		double r = basis;
		while (it.advance() != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	@SuppressWarnings("unchecked")
	public long reduceKeysToLongSequentially(ObjectToLong<? super K> transformer,
					long basis,
					LongByLongToLong reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		long r = basis;
		while (it.advance() != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	@SuppressWarnings("unchecked")
	public int reduceKeysToIntSequentially(ObjectToInt<? super K> transformer,
					int basis,
					IntByIntToInt reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		int r = basis;
		while (it.advance() != null)
			r = reducer.apply(r, transformer.apply((K) it.nextKey));
		return r;
	}

	/**
	 * Performs the given action for each value.
	 *
	 * @param action the action
	 */
	public void forEachValueSequentially(Action<V> action) {
		if (action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		while ((v = it.advance()) != null)
			action.apply(v);
	}

	/**
	 * Performs the given action for each non-null transformation of each value.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 */
	public <U> void forEachValueSequentially(Fun<? super V, ? extends U> transformer,
					Action<U> action) {
		if (transformer == null || action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply(v)) != null)
				action.apply(u);
		}
	}

	/**
	 * Returns a non-null result from applying the given search function on each value, or null if none.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each value, or null if none
	 */
	public <U> U searchValuesSequentially(Fun<? super V, ? extends U> searchFunction) {
		if (searchFunction == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = searchFunction.apply(v)) != null)
				return u;
		}
		return null;
	}

	/**
	 * Returns the result of accumulating all values using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all values
	 */
	public V reduceValuesSequentially(BiFun<? super V, ? super V, ? extends V> reducer) {
		if (reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V r = null;
		V v;
		while ((v = it.advance()) != null)
			r = (r == null) ? v : reducer.apply(r, v);
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public <U> U reduceValuesSequentially(Fun<? super V, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U r = null, u;
		V v;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply(v)) != null)
				r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public double reduceValuesToDoubleSequentially(ObjectToDouble<? super V> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		double r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(v));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public long reduceValuesToLongSequentially(ObjectToLong<? super V> transformer,
					long basis,
					LongByLongToLong reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		long r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(v));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public int reduceValuesToIntSequentially(ObjectToInt<? super V> transformer,
					int basis,
					IntByIntToInt reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		int r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(v));
		return r;
	}

	/**
	 * Performs the given action for each entry.
	 *
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public void forEachEntrySequentially(Action<Map.Entry<K, V>> action) {
		if (action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		while ((v = it.advance()) != null)
			action.apply(entryFor((K) it.nextKey, v));
	}

	/**
	 * Performs the given action for each non-null transformation of each entry.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	@SuppressWarnings("unchecked")
	public <U> void forEachEntrySequentially(Fun<Map.Entry<K, V>, ? extends U> transformer,
					Action<U> action) {
		if (transformer == null || action == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply(entryFor((K) it.nextKey, v))) != null)
				action.apply(u);
		}
	}

	/**
	 * Returns a non-null result from applying the given search function on each entry, or null if none.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each entry, or null if none
	 */
	@SuppressWarnings("unchecked")
	public <U> U searchEntriesSequentially(Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
		if (searchFunction == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		V v;
		U u;
		while ((v = it.advance()) != null) {
			if ((u = searchFunction.apply(entryFor((K) it.nextKey, v))) != null)
				return u;
		}
		return null;
	}

	/**
	 * Returns the result of accumulating all entries using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all entries
	 */
	@SuppressWarnings("unchecked")
	public Map.Entry<K, V> reduceEntriesSequentially(BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
		if (reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		Map.Entry<K, V> r = null;
		V v;
		while ((v = it.advance()) != null) {
			Map.Entry<K, V> u = entryFor((K) it.nextKey, v);
			r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	@SuppressWarnings("unchecked")
	public <U> U reduceEntriesSequentially(Fun<Map.Entry<K, V>, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		U r = null, u;
		V v;
		while ((v = it.advance()) != null) {
			if ((u = transformer.apply(entryFor((K) it.nextKey, v))) != null)
				r = (r == null) ? u : reducer.apply(r, u);
		}
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	@SuppressWarnings("unchecked")
	public double reduceEntriesToDoubleSequentially(ObjectToDouble<Map.Entry<K, V>> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		double r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	@SuppressWarnings("unchecked")
	public long reduceEntriesToLongSequentially(ObjectToLong<Map.Entry<K, V>> transformer,
					long basis,
					LongByLongToLong reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		long r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
		return r;
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	@SuppressWarnings("unchecked")
	public int reduceEntriesToIntSequentially(ObjectToInt<Map.Entry<K, V>> transformer,
					int basis,
					IntByIntToInt reducer) {
		if (transformer == null || reducer == null)
			throw new NullPointerException();
		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
		int r = basis;
		V v;
		while ((v = it.advance()) != null)
			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
		return r;
	}

	// Parallel bulk operations
	/**
	 * Performs the given action for each (key, value).
	 *
	 * @param action the action
	 */
	public void forEachInParallel(BiAction<K, V> action) {
		ForkJoinTasks.forEach(this, action).invoke();
	}

	/**
	 * Performs the given action for each non-null transformation of each (key, value).
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	public <U> void forEachInParallel(BiFun<? super K, ? super V, ? extends U> transformer,
					Action<U> action) {
		ForkJoinTasks.forEach(this, transformer, action).invoke();
	}

	/**
	 * Returns a non-null result from applying the given search function on each (key, value), or null if none. Upon success, further element
	 * processing is suppressed and the results of any other parallel invocations of the search function are ignored.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each (key, value), or null if none
	 */
	public <U> U searchInParallel(BiFun<? super K, ? super V, ? extends U> searchFunction) {
		return ForkJoinTasks.search(this, searchFunction).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, or
	 * null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	public <U> U reduceInParallel(BiFun<? super K, ? super V, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		return ForkJoinTasks.reduce(this, transformer, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	public double reduceToDoubleInParallel(ObjectByObjectToDouble<? super K, ? super V> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		return ForkJoinTasks.reduceToDouble(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	public long reduceToLongInParallel(ObjectByObjectToLong<? super K, ? super V> transformer,
					long basis,
					LongByLongToLong reducer) {
		return ForkJoinTasks.reduceToLong(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and
	 * the given basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all (key, value) pairs
	 */
	public int reduceToIntInParallel(ObjectByObjectToInt<? super K, ? super V> transformer,
					int basis,
					IntByIntToInt reducer) {
		return ForkJoinTasks.reduceToInt(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Performs the given action for each key.
	 *
	 * @param action the action
	 */
	public void forEachKeyInParallel(Action<K> action) {
		ForkJoinTasks.forEachKey(this, action).invoke();
	}

	/**
	 * Performs the given action for each non-null transformation of each key.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	public <U> void forEachKeyInParallel(Fun<? super K, ? extends U> transformer,
					Action<U> action) {
		ForkJoinTasks.forEachKey(this, transformer, action).invoke();
	}

	/**
	 * Returns a non-null result from applying the given search function on each key, or null if none. Upon success, further element
	 * processing is suppressed and the results of any other parallel invocations of the search function are ignored.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each key, or null if none
	 */
	public <U> U searchKeysInParallel(Fun<? super K, ? extends U> searchFunction) {
		return ForkJoinTasks.searchKeys(this, searchFunction).invoke();
	}

	/**
	 * Returns the result of accumulating all keys using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all keys using the given reducer to combine values, or null if none
	 */
	public K reduceKeysInParallel(BiFun<? super K, ? super K, ? extends K> reducer) {
		return ForkJoinTasks.reduceKeys(this, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	public <U> U reduceKeysInParallel(Fun<? super K, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		return ForkJoinTasks.reduceKeys(this, transformer, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	public double reduceKeysToDoubleInParallel(ObjectToDouble<? super K> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		return ForkJoinTasks.reduceKeysToDouble(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	public long reduceKeysToLongInParallel(ObjectToLong<? super K> transformer,
					long basis,
					LongByLongToLong reducer) {
		return ForkJoinTasks.reduceKeysToLong(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis
	 * as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all keys
	 */
	public int reduceKeysToIntInParallel(ObjectToInt<? super K> transformer,
					int basis,
					IntByIntToInt reducer) {
		return ForkJoinTasks.reduceKeysToInt(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Performs the given action for each value.
	 *
	 * @param action the action
	 */
	public void forEachValueInParallel(Action<V> action) {
		ForkJoinTasks.forEachValue(this, action).invoke();
	}

	/**
	 * Performs the given action for each non-null transformation of each value.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 */
	public <U> void forEachValueInParallel(Fun<? super V, ? extends U> transformer,
					Action<U> action) {
		ForkJoinTasks.forEachValue(this, transformer, action).invoke();
	}

	/**
	 * Returns a non-null result from applying the given search function on each value, or null if none. Upon success, further element
	 * processing is suppressed and the results of any other parallel invocations of the search function are ignored.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each value, or null if none
	 */
	public <U> U searchValuesInParallel(Fun<? super V, ? extends U> searchFunction) {
		return ForkJoinTasks.searchValues(this, searchFunction).invoke();
	}

	/**
	 * Returns the result of accumulating all values using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all values
	 */
	public V reduceValuesInParallel(BiFun<? super V, ? super V, ? extends V> reducer) {
		return ForkJoinTasks.reduceValues(this, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public <U> U reduceValuesInParallel(Fun<? super V, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		return ForkJoinTasks.reduceValues(this, transformer, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public double reduceValuesToDoubleInParallel(ObjectToDouble<? super V> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		return ForkJoinTasks.reduceValuesToDouble(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public long reduceValuesToLongInParallel(ObjectToLong<? super V> transformer,
					long basis,
					LongByLongToLong reducer) {
		return ForkJoinTasks.reduceValuesToLong(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all values
	 */
	public int reduceValuesToIntInParallel(ObjectToInt<? super V> transformer,
					int basis,
					IntByIntToInt reducer) {
		return ForkJoinTasks.reduceValuesToInt(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Performs the given action for each entry.
	 *
	 * @param action the action
	 */
	public void forEachEntryInParallel(Action<Map.Entry<K, V>> action) {
		ForkJoinTasks.forEachEntry(this, action).invoke();
	}

	/**
	 * Performs the given action for each non-null transformation of each entry.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
	 * action is not applied)
	 * @param action the action
	 */
	public <U> void forEachEntryInParallel(Fun<Map.Entry<K, V>, ? extends U> transformer,
					Action<U> action) {
		ForkJoinTasks.forEachEntry(this, transformer, action).invoke();
	}

	/**
	 * Returns a non-null result from applying the given search function on each entry, or null if none. Upon success, further element
	 * processing is suppressed and the results of any other parallel invocations of the search function are ignored.
	 *
	 * @param searchFunction a function returning a non-null result on success, else null
	 * @return a non-null result from applying the given search function on each entry, or null if none
	 */
	public <U> U searchEntriesInParallel(Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
		return ForkJoinTasks.searchEntries(this, searchFunction).invoke();
	}

	/**
	 * Returns the result of accumulating all entries using the given reducer to combine values, or null if none.
	 *
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating all entries
	 */
	public Map.Entry<K, V> reduceEntriesInParallel(BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
		return ForkJoinTasks.reduceEntries(this, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, or null if none.
	 *
	 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
	 * not combined)
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	public <U> U reduceEntriesInParallel(Fun<Map.Entry<K, V>, ? extends U> transformer,
					BiFun<? super U, ? super U, ? extends U> reducer) {
		return ForkJoinTasks.reduceEntries(this, transformer, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	public double reduceEntriesToDoubleInParallel(ObjectToDouble<Map.Entry<K, V>> transformer,
					double basis,
					DoubleByDoubleToDouble reducer) {
		return ForkJoinTasks.reduceEntriesToDouble(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	public long reduceEntriesToLongInParallel(ObjectToLong<Map.Entry<K, V>> transformer,
					long basis,
					LongByLongToLong reducer) {
		return ForkJoinTasks.reduceEntriesToLong(this, transformer, basis, reducer).invoke();
	}

	/**
	 * Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given
	 * basis as an identity value.
	 *
	 * @param transformer a function returning the transformation for an element
	 * @param basis the identity (initial default value) for the reduction
	 * @param reducer a commutative associative combining function
	 * @return the result of accumulating the given transformation of all entries
	 */
	public int reduceEntriesToIntInParallel(ObjectToInt<Map.Entry<K, V>> transformer,
					int basis,
					IntByIntToInt reducer) {
		return ForkJoinTasks.reduceEntriesToInt(this, transformer, basis, reducer).invoke();
	}


	/* ----------------Views -------------- */
	/**
	 * Base class for views.
	 */
	abstract static class CHMView<K, V> {

		final ConcurrentHashMapV8<K, V> map;

		CHMView(ConcurrentHashMapV8<K, V> map) {
			this.map = map;
		}

		/**
		 * Returns the map backing this view.
		 *
		 * @return the map backing this view
		 */
		public ConcurrentHashMapV8<K, V> getMap() {
			return map;
		}

		public final int size() {
			return map.size();
		}

		public final boolean isEmpty() {
			return map.isEmpty();
		}

		public final void clear() {
			map.clear();
		}

		// implementations below rely on concrete classes supplying these
		public abstract Iterator<?> iterator();

		public abstract boolean contains(Object o);

		public abstract boolean remove(Object o);
		private static final String oomeMsg = "Required array size too large";

		public final Object[] toArray() {
			long sz = map.mappingCount();
			if (sz > (long) (MAX_ARRAY_SIZE))
				throw new OutOfMemoryError(oomeMsg);
			int n = (int) sz;
			Object[] r = new Object[n];
			int i = 0;
			Iterator<?> it = iterator();
			while (it.hasNext()) {
				if (i == n) {
					if (n >= MAX_ARRAY_SIZE)
						throw new OutOfMemoryError(oomeMsg);
					if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
						n = MAX_ARRAY_SIZE;
					else
						n += (n >>> 1) + 1;
					r = Arrays.copyOf(r, n);
				}
				r[i++] = it.next();
			}
			return (i == n) ? r : Arrays.copyOf(r, i);
		}

		@SuppressWarnings("unchecked")
		public final <T> T[] toArray(T[] a) {
			long sz = map.mappingCount();
			if (sz > (long) (MAX_ARRAY_SIZE))
				throw new OutOfMemoryError(oomeMsg);
			int m = (int) sz;
			T[] r = (a.length >= m) ? a
							: (T[]) java.lang.reflect.Array
							.newInstance(a.getClass().getComponentType(), m);
			int n = r.length;
			int i = 0;
			Iterator<?> it = iterator();
			while (it.hasNext()) {
				if (i == n) {
					if (n >= MAX_ARRAY_SIZE)
						throw new OutOfMemoryError(oomeMsg);
					if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
						n = MAX_ARRAY_SIZE;
					else
						n += (n >>> 1) + 1;
					r = Arrays.copyOf(r, n);
				}
				r[i++] = (T) it.next();
			}
			if (a == r && i < n) {
				r[i] = null; // null-terminate
				return r;
			}
			return (i == n) ? r : Arrays.copyOf(r, i);
		}

		public final int hashCode() {
			int h = 0;
			for (Iterator<?> it = iterator(); it.hasNext();)
				h += it.next().hashCode();
			return h;
		}

		public final String toString() {
			StringBuilder sb = new StringBuilder();
			sb.append('[');
			Iterator<?> it = iterator();
			if (it.hasNext()) {
				for (;;) {
					Object e = it.next();
					sb.append(e == this ? "(this Collection)" : e);
					if (!it.hasNext())
						break;
					sb.append(',').append(' ');
				}
			}
			return sb.append(']').toString();
		}

		public final boolean containsAll(Collection<?> c) {
			if (c != this) {
				for (Iterator<?> it = c.iterator(); it.hasNext();) {
					Object e = it.next();
					if (e == null || !contains(e))
						return false;
				}
			}
			return true;
		}

		public final boolean removeAll(Collection<?> c) {
			boolean modified = false;
			for (Iterator<?> it = iterator(); it.hasNext();) {
				if (c.contains(it.next())) {
					it.remove();
					modified = true;
				}
			}
			return modified;
		}

		public final boolean retainAll(Collection<?> c) {
			boolean modified = false;
			for (Iterator<?> it = iterator(); it.hasNext();) {
				if (!c.contains(it.next())) {
					it.remove();
					modified = true;
				}
			}
			return modified;
		}
	}

	/**
	 * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in which additions may optionally be enabled by mapping to a common value.
	 * This class cannot be directly instantiated. See 	 {@link #keySet()}, {@link #keySet(Object)}, {@link #newKeySet()},
     * {@link #newKeySet(int)}.
	 */
	public static class KeySetView<K, V> extends CHMView<K, V>
					implements Set<K>, java.io.Serializable {

		private static final long serialVersionUID = 7249069246763182397L;
		private final V value;

		KeySetView(ConcurrentHashMapV8<K, V> map, V value) {  // non-public
			super(map);
			this.value = value;
		}

		/**
		 * Returns the default mapped value for additions, or {@code null} if additions are not supported.
		 *
		 * @return the default mapped value for additions, or {@code null} if not supported
		 */
		public V getMappedValue() {
			return value;
		}

		// implement Set API
		public boolean contains(Object o) {
			return map.containsKey(o);
		}

		public boolean remove(Object o) {
			return map.remove(o) != null;
		}

		/**
		 * Returns a "weakly consistent" iterator that will never throw {@link ConcurrentModificationException}, and guarantees to traverse
		 * elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent
		 * to construction.
		 *
		 * @return an iterator over the keys of this map
		 */
		public Iterator<K> iterator() {
			return new KeyIterator<K, V>(map);
		}

		public boolean add(K e) {
			V v;
			if ((v = value) == null)
				throw new UnsupportedOperationException();
			return map.internalPut(e, v, true) == null;
		}

		public boolean addAll(Collection<? extends K> c) {
			boolean added = false;
			V v;
			if ((v = value) == null)
				throw new UnsupportedOperationException();
			for (K e : c) {
				if (map.internalPut(e, v, true) == null)
					added = true;
			}
			return added;
		}

		public boolean equals(Object o) {
			Set<?> c;
			return ((o instanceof Set)
							&& ((c = (Set<?>) o) == this
							|| (containsAll(c) && c.containsAll(this))));
		}
	}

	/**
	 * A view of a ConcurrentHashMapV8 as a {@link Collection} of values, in which additions are disabled. This class cannot be directly
	 * instantiated. See {@link #values()}.
	 *
	 * <p>The view's {@code iterator} is a "weakly consistent" iterator that will never throw {@link ConcurrentModificationException}, and
	 * guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any
	 * modifications subsequent to construction.
	 */
	public static final class ValuesView<K, V> extends CHMView<K, V>
					implements Collection<V> {

		ValuesView(ConcurrentHashMapV8<K, V> map) {
			super(map);
		}

		public final boolean contains(Object o) {
			return map.containsValue(o);
		}

		public final boolean remove(Object o) {
			if (o != null) {
				Iterator<V> it = new ValueIterator<K, V>(map);
				while (it.hasNext()) {
					if (o.equals(it.next())) {
						it.remove();
						return true;
					}
				}
			}
			return false;
		}

		/**
		 * Returns a "weakly consistent" iterator that will never throw {@link ConcurrentModificationException}, and guarantees to traverse
		 * elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent
		 * to construction.
		 *
		 * @return an iterator over the values of this map
		 */
		public final Iterator<V> iterator() {
			return new ValueIterator<K, V>(map);
		}

		public final boolean add(V e) {
			throw new UnsupportedOperationException();
		}

		public final boolean addAll(Collection<? extends V> c) {
			throw new UnsupportedOperationException();
		}
	}

	/**
	 * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value) entries. This class cannot be directly instantiated. See
	 * {@link #entrySet()}.
	 */
	public static final class EntrySetView<K, V> extends CHMView<K, V>
					implements Set<Map.Entry<K, V>> {

		EntrySetView(ConcurrentHashMapV8<K, V> map) {
			super(map);
		}

		public final boolean contains(Object o) {
			Object k, v, r;
			Map.Entry<?, ?> e;
			return ((o instanceof Map.Entry)
							&& (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
							&& (r = map.get(k)) != null
							&& (v = e.getValue()) != null
							&& (v == r || v.equals(r)));
		}

		public final boolean remove(Object o) {
			Object k, v;
			Map.Entry<?, ?> e;
			return ((o instanceof Map.Entry)
							&& (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
							&& (v = e.getValue()) != null
							&& map.remove(k, v));
		}

		/**
		 * Returns a "weakly consistent" iterator that will never throw {@link ConcurrentModificationException}, and guarantees to traverse
		 * elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent
		 * to construction.
		 *
		 * @return an iterator over the entries of this map
		 */
		public final Iterator<Map.Entry<K, V>> iterator() {
			return new EntryIterator<K, V>(map);
		}

		public final boolean add(Entry<K, V> e) {
			return map.internalPut(e.getKey(), e.getValue(), false) == null;
		}

		public final boolean addAll(Collection<? extends Entry<K, V>> c) {
			boolean added = false;
			for (Entry<K, V> e : c) {
				if (add(e))
					added = true;
			}
			return added;
		}

		public boolean equals(Object o) {
			Set<?> c;
			return ((o instanceof Set)
							&& ((c = (Set<?>) o) == this
							|| (containsAll(c) && c.containsAll(this))));
		}
	}

	// ---------------------------------------------------------------------
	/**
	 * Predefined tasks for performing bulk parallel operations on ConcurrentHashMapV8s. These tasks follow the forms and rules used for bulk
	 * operations. Each method has the same name, but returns a task rather than invoking it. These methods may be useful in custom
	 * applications such as submitting a task without waiting for completion, using a custom pool, or combining with other tasks.
	 */
	public static class ForkJoinTasks {

		private ForkJoinTasks() {
		}

		/**
		 * Returns a task that when invoked, performs the given action for each (key, value)
		 *
		 * @param map the map
		 * @param action the action
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Void> forEach(ConcurrentHashMapV8<K, V> map,
						BiAction<K, V> action) {
			if (action == null)
				throw new NullPointerException();
			return new ForEachMappingTask<K, V>(map, null, -1, action);
		}

		/**
		 * Returns a task that when invoked, performs the given action for each non-null transformation of each (key, value)
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
		 * action is not applied)
		 * @param action the action
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<Void> forEach(ConcurrentHashMapV8<K, V> map,
						BiFun<? super K, ? super V, ? extends U> transformer,
						Action<U> action) {
			if (transformer == null || action == null)
				throw new NullPointerException();
			return new ForEachTransformedMappingTask<K, V, U>(map, null, -1, transformer, action);
		}

		/**
		 * Returns a task that when invoked, returns a non-null result from applying the given search function on each (key, value), or null if
		 * none. Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function
		 * are ignored.
		 *
		 * @param map the map
		 * @param searchFunction a function returning a non-null result on success, else null
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> search(ConcurrentHashMapV8<K, V> map,
						BiFun<? super K, ? super V, ? extends U> searchFunction) {
			if (searchFunction == null)
				throw new NullPointerException();
			return new SearchMappingsTask<K, V, U>(map, null, -1, searchFunction,
							new AtomicReference<U>());
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all (key, value) pairs using the
		 * given reducer to combine values, or null if none.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
		 * not combined)
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> reduce(ConcurrentHashMapV8<K, V> map,
						BiFun<? super K, ? super V, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceMappingsTask<K, V, U>(map, null, -1, null, transformer, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all (key, value) pairs using the
		 * given reducer to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Double> reduceToDouble(ConcurrentHashMapV8<K, V> map,
						ObjectByObjectToDouble<? super K, ? super V> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceMappingsToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all (key, value) pairs using the
		 * given reducer to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Long> reduceToLong(ConcurrentHashMapV8<K, V> map,
						ObjectByObjectToLong<? super K, ? super V> transformer,
						long basis,
						LongByLongToLong reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceMappingsToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all (key, value) pairs using the
		 * given reducer to combine values, and the given basis as an identity value.
		 *
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Integer> reduceToInt(ConcurrentHashMapV8<K, V> map,
						ObjectByObjectToInt<? super K, ? super V> transformer,
						int basis,
						IntByIntToInt reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceMappingsToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, performs the given action for each key.
		 *
		 * @param map the map
		 * @param action the action
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Void> forEachKey(ConcurrentHashMapV8<K, V> map,
						Action<K> action) {
			if (action == null)
				throw new NullPointerException();
			return new ForEachKeyTask<K, V>(map, null, -1, action);
		}

		/**
		 * Returns a task that when invoked, performs the given action for each non-null transformation of each key.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
		 * action is not applied)
		 * @param action the action
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<Void> forEachKey(ConcurrentHashMapV8<K, V> map,
						Fun<? super K, ? extends U> transformer,
						Action<U> action) {
			if (transformer == null || action == null)
				throw new NullPointerException();
			return new ForEachTransformedKeyTask<K, V, U>(map, null, -1, transformer, action);
		}

		/**
		 * Returns a task that when invoked, returns a non-null result from applying the given search function on each key, or null if none.
		 * Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are
		 * ignored.
		 *
		 * @param map the map
		 * @param searchFunction a function returning a non-null result on success, else null
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> searchKeys(ConcurrentHashMapV8<K, V> map,
						Fun<? super K, ? extends U> searchFunction) {
			if (searchFunction == null)
				throw new NullPointerException();
			return new SearchKeysTask<K, V, U>(map, null, -1, searchFunction,
							new AtomicReference<U>());
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating all keys using the given reducer to combine values, or null if
		 * none.
		 *
		 * @param map the map
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<K> reduceKeys(ConcurrentHashMapV8<K, V> map,
						BiFun<? super K, ? super K, ? extends K> reducer) {
			if (reducer == null)
				throw new NullPointerException();
			return new ReduceKeysTask<K, V>(map, null, -1, null, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all keys using the given reducer to
		 * combine values, or null if none.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
		 * not combined)
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> reduceKeys(ConcurrentHashMapV8<K, V> map,
						Fun<? super K, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceKeysTask<K, V, U>(map, null, -1, null, transformer, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all keys using the given reducer to
		 * combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Double> reduceKeysToDouble(ConcurrentHashMapV8<K, V> map,
						ObjectToDouble<? super K> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceKeysToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all keys using the given reducer to
		 * combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Long> reduceKeysToLong(ConcurrentHashMapV8<K, V> map,
						ObjectToLong<? super K> transformer,
						long basis,
						LongByLongToLong reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceKeysToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all keys using the given reducer to
		 * combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Integer> reduceKeysToInt(ConcurrentHashMapV8<K, V> map,
						ObjectToInt<? super K> transformer,
						int basis,
						IntByIntToInt reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceKeysToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, performs the given action for each value.
		 *
		 * @param map the map
		 * @param action the action
		 */
		public static <K, V> ForkJoinTask<Void> forEachValue(ConcurrentHashMapV8<K, V> map,
						Action<V> action) {
			if (action == null)
				throw new NullPointerException();
			return new ForEachValueTask<K, V>(map, null, -1, action);
		}

		/**
		 * Returns a task that when invoked, performs the given action for each non-null transformation of each value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
		 * action is not applied)
		 * @param action the action
		 */
		public static <K, V, U> ForkJoinTask<Void> forEachValue(ConcurrentHashMapV8<K, V> map,
						Fun<? super V, ? extends U> transformer,
						Action<U> action) {
			if (transformer == null || action == null)
				throw new NullPointerException();
			return new ForEachTransformedValueTask<K, V, U>(map, null, -1, transformer, action);
		}

		/**
		 * Returns a task that when invoked, returns a non-null result from applying the given search function on each value, or null if none.
		 * Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are
		 * ignored.
		 *
		 * @param map the map
		 * @param searchFunction a function returning a non-null result on success, else null
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> searchValues(ConcurrentHashMapV8<K, V> map,
						Fun<? super V, ? extends U> searchFunction) {
			if (searchFunction == null)
				throw new NullPointerException();
			return new SearchValuesTask<K, V, U>(map, null, -1, searchFunction,
							new AtomicReference<U>());
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating all values using the given reducer to combine values, or null if
		 * none.
		 *
		 * @param map the map
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<V> reduceValues(ConcurrentHashMapV8<K, V> map,
						BiFun<? super V, ? super V, ? extends V> reducer) {
			if (reducer == null)
				throw new NullPointerException();
			return new ReduceValuesTask<K, V>(map, null, -1, null, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all values using the given reducer
		 * to combine values, or null if none.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
		 * not combined)
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> reduceValues(ConcurrentHashMapV8<K, V> map,
						Fun<? super V, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceValuesTask<K, V, U>(map, null, -1, null, transformer, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all values using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Double> reduceValuesToDouble(ConcurrentHashMapV8<K, V> map,
						ObjectToDouble<? super V> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceValuesToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all values using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Long> reduceValuesToLong(ConcurrentHashMapV8<K, V> map,
						ObjectToLong<? super V> transformer,
						long basis,
						LongByLongToLong reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceValuesToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all values using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Integer> reduceValuesToInt(ConcurrentHashMapV8<K, V> map,
						ObjectToInt<? super V> transformer,
						int basis,
						IntByIntToInt reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceValuesToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, perform the given action for each entry.
		 *
		 * @param map the map
		 * @param action the action
		 */
		public static <K, V> ForkJoinTask<Void> forEachEntry(ConcurrentHashMapV8<K, V> map,
						Action<Map.Entry<K, V>> action) {
			if (action == null)
				throw new NullPointerException();
			return new ForEachEntryTask<K, V>(map, null, -1, action);
		}

		/**
		 * Returns a task that when invoked, perform the given action for each non-null transformation of each entry.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case the
		 * action is not applied)
		 * @param action the action
		 */
		public static <K, V, U> ForkJoinTask<Void> forEachEntry(ConcurrentHashMapV8<K, V> map,
						Fun<Map.Entry<K, V>, ? extends U> transformer,
						Action<U> action) {
			if (transformer == null || action == null)
				throw new NullPointerException();
			return new ForEachTransformedEntryTask<K, V, U>(map, null, -1, transformer, action);
		}

		/**
		 * Returns a task that when invoked, returns a non-null result from applying the given search function on each entry, or null if none.
		 * Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are
		 * ignored.
		 *
		 * @param map the map
		 * @param searchFunction a function returning a non-null result on success, else null
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> searchEntries(ConcurrentHashMapV8<K, V> map,
						Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
			if (searchFunction == null)
				throw new NullPointerException();
			return new SearchEntriesTask<K, V, U>(map, null, -1, searchFunction,
							new AtomicReference<U>());
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating all entries using the given reducer to combine values, or null
		 * if none.
		 *
		 * @param map the map
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Map.Entry<K, V>> reduceEntries(ConcurrentHashMapV8<K, V> map,
						BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
			if (reducer == null)
				throw new NullPointerException();
			return new ReduceEntriesTask<K, V>(map, null, -1, null, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all entries using the given reducer
		 * to combine values, or null if none.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element, or null if there is no transformation (in which case it is
		 * not combined)
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V, U> ForkJoinTask<U> reduceEntries(ConcurrentHashMapV8<K, V> map,
						Fun<Map.Entry<K, V>, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceEntriesTask<K, V, U>(map, null, -1, null, transformer, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all entries using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Double> reduceEntriesToDouble(ConcurrentHashMapV8<K, V> map,
						ObjectToDouble<Map.Entry<K, V>> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceEntriesToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all entries using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Long> reduceEntriesToLong(ConcurrentHashMapV8<K, V> map,
						ObjectToLong<Map.Entry<K, V>> transformer,
						long basis,
						LongByLongToLong reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceEntriesToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}

		/**
		 * Returns a task that when invoked, returns the result of accumulating the given transformation of all entries using the given reducer
		 * to combine values, and the given basis as an identity value.
		 *
		 * @param map the map
		 * @param transformer a function returning the transformation for an element
		 * @param basis the identity (initial default value) for the reduction
		 * @param reducer a commutative associative combining function
		 * @return the task
		 */
		public static <K, V> ForkJoinTask<Integer> reduceEntriesToInt(ConcurrentHashMapV8<K, V> map,
						ObjectToInt<Map.Entry<K, V>> transformer,
						int basis,
						IntByIntToInt reducer) {
			if (transformer == null || reducer == null)
				throw new NullPointerException();
			return new MapReduceEntriesToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
		}
	}

	// -------------------------------------------------------

	/*
	 * Task classes. Coded in a regular but ugly format/style to
	 * simplify checks that each variant differs in the right way from
	 * others. The null screenings exist because compilers cannot tell
	 * that we've already null-checked task arguments, so we force
	 * simplest hoisted bypass to help avoid convoluted traps.
	 */
	@SuppressWarnings("serial")
	static final class ForEachKeyTask<K, V>
					extends Traverser<K, V, Void> {

		final Action<K> action;

		ForEachKeyTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Action<K> action) {
			super(m, p, b);
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Action<K> action;
			if ((action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachKeyTask<K, V>(map, this, b, action).fork();
				while (advance() != null)
					action.apply((K) nextKey);
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachValueTask<K, V>
					extends Traverser<K, V, Void> {

		final Action<V> action;

		ForEachValueTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Action<V> action) {
			super(m, p, b);
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Action<V> action;
			if ((action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachValueTask<K, V>(map, this, b, action).fork();
				V v;
				while ((v = advance()) != null)
					action.apply(v);
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachEntryTask<K, V>
					extends Traverser<K, V, Void> {

		final Action<Entry<K, V>> action;

		ForEachEntryTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Action<Entry<K, V>> action) {
			super(m, p, b);
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Action<Entry<K, V>> action;
			if ((action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachEntryTask<K, V>(map, this, b, action).fork();
				V v;
				while ((v = advance()) != null)
					action.apply(entryFor((K) nextKey, v));
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachMappingTask<K, V>
					extends Traverser<K, V, Void> {

		final BiAction<K, V> action;

		ForEachMappingTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						BiAction<K, V> action) {
			super(m, p, b);
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiAction<K, V> action;
			if ((action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachMappingTask<K, V>(map, this, b, action).fork();
				V v;
				while ((v = advance()) != null)
					action.apply((K) nextKey, v);
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachTransformedKeyTask<K, V, U>
					extends Traverser<K, V, Void> {

		final Fun<? super K, ? extends U> transformer;
		final Action<U> action;

		ForEachTransformedKeyTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<? super K, ? extends U> transformer, Action<U> action) {
			super(m, p, b);
			this.transformer = transformer;
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super K, ? extends U> transformer;
			final Action<U> action;
			if ((transformer = this.transformer) != null
							&& (action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachTransformedKeyTask<K, V, U>(map, this, b, transformer, action).fork();
				U u;
				while (advance() != null) {
					if ((u = transformer.apply((K) nextKey)) != null)
						action.apply(u);
				}
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachTransformedValueTask<K, V, U>
					extends Traverser<K, V, Void> {

		final Fun<? super V, ? extends U> transformer;
		final Action<U> action;

		ForEachTransformedValueTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<? super V, ? extends U> transformer, Action<U> action) {
			super(m, p, b);
			this.transformer = transformer;
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super V, ? extends U> transformer;
			final Action<U> action;
			if ((transformer = this.transformer) != null
							&& (action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachTransformedValueTask<K, V, U>(map, this, b, transformer, action).fork();
				V v;
				U u;
				while ((v = advance()) != null) {
					if ((u = transformer.apply(v)) != null)
						action.apply(u);
				}
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachTransformedEntryTask<K, V, U>
					extends Traverser<K, V, Void> {

		final Fun<Map.Entry<K, V>, ? extends U> transformer;
		final Action<U> action;

		ForEachTransformedEntryTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<Map.Entry<K, V>, ? extends U> transformer, Action<U> action) {
			super(m, p, b);
			this.transformer = transformer;
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<Map.Entry<K, V>, ? extends U> transformer;
			final Action<U> action;
			if ((transformer = this.transformer) != null
							&& (action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachTransformedEntryTask<K, V, U>(map, this, b, transformer, action).fork();
				V v;
				U u;
				while ((v = advance()) != null) {
					if ((u = transformer.apply(entryFor((K) nextKey,
									v))) != null)
						action.apply(u);
				}
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ForEachTransformedMappingTask<K, V, U>
					extends Traverser<K, V, Void> {

		final BiFun<? super K, ? super V, ? extends U> transformer;
		final Action<U> action;

		ForEachTransformedMappingTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						BiFun<? super K, ? super V, ? extends U> transformer,
						Action<U> action) {
			super(m, p, b);
			this.transformer = transformer;
			this.action = action;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<? super K, ? super V, ? extends U> transformer;
			final Action<U> action;
			if ((transformer = this.transformer) != null
							&& (action = this.action) != null) {
				for (int b; (b = preSplit()) > 0;)
					new ForEachTransformedMappingTask<K, V, U>(map, this, b, transformer, action).fork();
				V v;
				U u;
				while ((v = advance()) != null) {
					if ((u = transformer.apply((K) nextKey, v)) != null)
						action.apply(u);
				}
				propagateCompletion();
			}
		}
	}

	@SuppressWarnings("serial")
	static final class SearchKeysTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<? super K, ? extends U> searchFunction;
		final AtomicReference<U> result;

		SearchKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<? super K, ? extends U> searchFunction,
						AtomicReference<U> result) {
			super(m, p, b);
			this.searchFunction = searchFunction;
			this.result = result;
		}

		public final U getRawResult() {
			return result.get();
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super K, ? extends U> searchFunction;
			final AtomicReference<U> result;
			if ((searchFunction = this.searchFunction) != null
							&& (result = this.result) != null) {
				for (int b;;) {
					if (result.get() != null)
						return;
					if ((b = preSplit()) <= 0)
						break;
					new SearchKeysTask<K, V, U>(map, this, b, searchFunction, result).fork();
				}
				while (result.get() == null) {
					U u;
					if (advance() == null) {
						propagateCompletion();
						break;
					}
					if ((u = searchFunction.apply((K) nextKey)) != null) {
						if (result.compareAndSet(null, u))
							quietlyCompleteRoot();
						break;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class SearchValuesTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<? super V, ? extends U> searchFunction;
		final AtomicReference<U> result;

		SearchValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<? super V, ? extends U> searchFunction,
						AtomicReference<U> result) {
			super(m, p, b);
			this.searchFunction = searchFunction;
			this.result = result;
		}

		public final U getRawResult() {
			return result.get();
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super V, ? extends U> searchFunction;
			final AtomicReference<U> result;
			if ((searchFunction = this.searchFunction) != null
							&& (result = this.result) != null) {
				for (int b;;) {
					if (result.get() != null)
						return;
					if ((b = preSplit()) <= 0)
						break;
					new SearchValuesTask<K, V, U>(map, this, b, searchFunction, result).fork();
				}
				while (result.get() == null) {
					V v;
					U u;
					if ((v = advance()) == null) {
						propagateCompletion();
						break;
					}
					if ((u = searchFunction.apply(v)) != null) {
						if (result.compareAndSet(null, u))
							quietlyCompleteRoot();
						break;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class SearchEntriesTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<Entry<K, V>, ? extends U> searchFunction;
		final AtomicReference<U> result;

		SearchEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						Fun<Entry<K, V>, ? extends U> searchFunction,
						AtomicReference<U> result) {
			super(m, p, b);
			this.searchFunction = searchFunction;
			this.result = result;
		}

		public final U getRawResult() {
			return result.get();
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<Entry<K, V>, ? extends U> searchFunction;
			final AtomicReference<U> result;
			if ((searchFunction = this.searchFunction) != null
							&& (result = this.result) != null) {
				for (int b;;) {
					if (result.get() != null)
						return;
					if ((b = preSplit()) <= 0)
						break;
					new SearchEntriesTask<K, V, U>(map, this, b, searchFunction, result).fork();
				}
				while (result.get() == null) {
					V v;
					U u;
					if ((v = advance()) == null) {
						propagateCompletion();
						break;
					}
					if ((u = searchFunction.apply(entryFor((K) nextKey,
									v))) != null) {
						if (result.compareAndSet(null, u))
							quietlyCompleteRoot();
						return;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class SearchMappingsTask<K, V, U>
					extends Traverser<K, V, U> {

		final BiFun<? super K, ? super V, ? extends U> searchFunction;
		final AtomicReference<U> result;

		SearchMappingsTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						BiFun<? super K, ? super V, ? extends U> searchFunction,
						AtomicReference<U> result) {
			super(m, p, b);
			this.searchFunction = searchFunction;
			this.result = result;
		}

		public final U getRawResult() {
			return result.get();
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<? super K, ? super V, ? extends U> searchFunction;
			final AtomicReference<U> result;
			if ((searchFunction = this.searchFunction) != null
							&& (result = this.result) != null) {
				for (int b;;) {
					if (result.get() != null)
						return;
					if ((b = preSplit()) <= 0)
						break;
					new SearchMappingsTask<K, V, U>(map, this, b, searchFunction, result).fork();
				}
				while (result.get() == null) {
					V v;
					U u;
					if ((v = advance()) == null) {
						propagateCompletion();
						break;
					}
					if ((u = searchFunction.apply((K) nextKey, v)) != null) {
						if (result.compareAndSet(null, u))
							quietlyCompleteRoot();
						break;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ReduceKeysTask<K, V>
					extends Traverser<K, V, K> {

		final BiFun<? super K, ? super K, ? extends K> reducer;
		K result;
		ReduceKeysTask<K, V> rights, nextRight;

		ReduceKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						ReduceKeysTask<K, V> nextRight,
						BiFun<? super K, ? super K, ? extends K> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.reducer = reducer;
		}

		public final K getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<? super K, ? super K, ? extends K> reducer;
			if ((reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new ReduceKeysTask<K, V>(map, this, b, rights, reducer)).fork();
				K r = null;
				while (advance() != null) {
					K u = (K) nextKey;
					r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					ReduceKeysTask<K, V> t = (ReduceKeysTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						K tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ReduceValuesTask<K, V>
					extends Traverser<K, V, V> {

		final BiFun<? super V, ? super V, ? extends V> reducer;
		V result;
		ReduceValuesTask<K, V> rights, nextRight;

		ReduceValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						ReduceValuesTask<K, V> nextRight,
						BiFun<? super V, ? super V, ? extends V> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.reducer = reducer;
		}

		public final V getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<? super V, ? super V, ? extends V> reducer;
			if ((reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new ReduceValuesTask<K, V>(map, this, b, rights, reducer)).fork();
				V r = null;
				V v;
				while ((v = advance()) != null) {
					V u = v;
					r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					ReduceValuesTask<K, V> t = (ReduceValuesTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						V tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class ReduceEntriesTask<K, V>
					extends Traverser<K, V, Map.Entry<K, V>> {

		final BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer;
		Map.Entry<K, V> result;
		ReduceEntriesTask<K, V> rights, nextRight;

		ReduceEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						ReduceEntriesTask<K, V> nextRight,
						BiFun<Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.reducer = reducer;
		}

		public final Map.Entry<K, V> getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer;
			if ((reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new ReduceEntriesTask<K, V>(map, this, b, rights, reducer)).fork();
				Map.Entry<K, V> r = null;
				V v;
				while ((v = advance()) != null) {
					Map.Entry<K, V> u = entryFor((K) nextKey, v);
					r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					ReduceEntriesTask<K, V> t = (ReduceEntriesTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						Map.Entry<K, V> tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceKeysTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<? super K, ? extends U> transformer;
		final BiFun<? super U, ? super U, ? extends U> reducer;
		U result;
		MapReduceKeysTask<K, V, U> rights, nextRight;

		MapReduceKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceKeysTask<K, V, U> nextRight,
						Fun<? super K, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.reducer = reducer;
		}

		public final U getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super K, ? extends U> transformer;
			final BiFun<? super U, ? super U, ? extends U> reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceKeysTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
				U r = null, u;
				while (advance() != null) {
					if ((u = transformer.apply((K) nextKey)) != null)
						r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceKeysTask<K, V, U> t = (MapReduceKeysTask<K, V, U>) c,
									s = t.rights;
					while (s != null) {
						U tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceValuesTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<? super V, ? extends U> transformer;
		final BiFun<? super U, ? super U, ? extends U> reducer;
		U result;
		MapReduceValuesTask<K, V, U> rights, nextRight;

		MapReduceValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceValuesTask<K, V, U> nextRight,
						Fun<? super V, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.reducer = reducer;
		}

		public final U getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<? super V, ? extends U> transformer;
			final BiFun<? super U, ? super U, ? extends U> reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceValuesTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
				U r = null, u;
				V v;
				while ((v = advance()) != null) {
					if ((u = transformer.apply(v)) != null)
						r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceValuesTask<K, V, U> t = (MapReduceValuesTask<K, V, U>) c,
									s = t.rights;
					while (s != null) {
						U tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceEntriesTask<K, V, U>
					extends Traverser<K, V, U> {

		final Fun<Map.Entry<K, V>, ? extends U> transformer;
		final BiFun<? super U, ? super U, ? extends U> reducer;
		U result;
		MapReduceEntriesTask<K, V, U> rights, nextRight;

		MapReduceEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceEntriesTask<K, V, U> nextRight,
						Fun<Map.Entry<K, V>, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.reducer = reducer;
		}

		public final U getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final Fun<Map.Entry<K, V>, ? extends U> transformer;
			final BiFun<? super U, ? super U, ? extends U> reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceEntriesTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
				U r = null, u;
				V v;
				while ((v = advance()) != null) {
					if ((u = transformer.apply(entryFor((K) nextKey,
									v))) != null)
						r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceEntriesTask<K, V, U> t = (MapReduceEntriesTask<K, V, U>) c,
									s = t.rights;
					while (s != null) {
						U tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceMappingsTask<K, V, U>
					extends Traverser<K, V, U> {

		final BiFun<? super K, ? super V, ? extends U> transformer;
		final BiFun<? super U, ? super U, ? extends U> reducer;
		U result;
		MapReduceMappingsTask<K, V, U> rights, nextRight;

		MapReduceMappingsTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceMappingsTask<K, V, U> nextRight,
						BiFun<? super K, ? super V, ? extends U> transformer,
						BiFun<? super U, ? super U, ? extends U> reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.reducer = reducer;
		}

		public final U getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final BiFun<? super K, ? super V, ? extends U> transformer;
			final BiFun<? super U, ? super U, ? extends U> reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceMappingsTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
				U r = null, u;
				V v;
				while ((v = advance()) != null) {
					if ((u = transformer.apply((K) nextKey, v)) != null)
						r = (r == null) ? u : reducer.apply(r, u);
				}
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceMappingsTask<K, V, U> t = (MapReduceMappingsTask<K, V, U>) c,
									s = t.rights;
					while (s != null) {
						U tr, sr;
						if ((sr = s.result) != null)
							t.result = (((tr = t.result) == null) ? sr
											: reducer.apply(tr, sr));
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceKeysToDoubleTask<K, V>
					extends Traverser<K, V, Double> {

		final ObjectToDouble<? super K> transformer;
		final DoubleByDoubleToDouble reducer;
		final double basis;
		double result;
		MapReduceKeysToDoubleTask<K, V> rights, nextRight;

		MapReduceKeysToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceKeysToDoubleTask<K, V> nextRight,
						ObjectToDouble<? super K> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Double getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToDouble<? super K> transformer;
			final DoubleByDoubleToDouble reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				double r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceKeysToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				while (advance() != null)
					r = reducer.apply(r, transformer.apply((K) nextKey));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceKeysToDoubleTask<K, V> t = (MapReduceKeysToDoubleTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceValuesToDoubleTask<K, V>
					extends Traverser<K, V, Double> {

		final ObjectToDouble<? super V> transformer;
		final DoubleByDoubleToDouble reducer;
		final double basis;
		double result;
		MapReduceValuesToDoubleTask<K, V> rights, nextRight;

		MapReduceValuesToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceValuesToDoubleTask<K, V> nextRight,
						ObjectToDouble<? super V> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Double getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToDouble<? super V> transformer;
			final DoubleByDoubleToDouble reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				double r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceValuesToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceValuesToDoubleTask<K, V> t = (MapReduceValuesToDoubleTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceEntriesToDoubleTask<K, V>
					extends Traverser<K, V, Double> {

		final ObjectToDouble<Map.Entry<K, V>> transformer;
		final DoubleByDoubleToDouble reducer;
		final double basis;
		double result;
		MapReduceEntriesToDoubleTask<K, V> rights, nextRight;

		MapReduceEntriesToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceEntriesToDoubleTask<K, V> nextRight,
						ObjectToDouble<Map.Entry<K, V>> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Double getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToDouble<Map.Entry<K, V>> transformer;
			final DoubleByDoubleToDouble reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				double r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceEntriesToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey,
									v)));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceEntriesToDoubleTask<K, V> t = (MapReduceEntriesToDoubleTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceMappingsToDoubleTask<K, V>
					extends Traverser<K, V, Double> {

		final ObjectByObjectToDouble<? super K, ? super V> transformer;
		final DoubleByDoubleToDouble reducer;
		final double basis;
		double result;
		MapReduceMappingsToDoubleTask<K, V> rights, nextRight;

		MapReduceMappingsToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceMappingsToDoubleTask<K, V> nextRight,
						ObjectByObjectToDouble<? super K, ? super V> transformer,
						double basis,
						DoubleByDoubleToDouble reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Double getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectByObjectToDouble<? super K, ? super V> transformer;
			final DoubleByDoubleToDouble reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				double r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceMappingsToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply((K) nextKey, v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceMappingsToDoubleTask<K, V> t = (MapReduceMappingsToDoubleTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceKeysToLongTask<K, V>
					extends Traverser<K, V, Long> {

		final ObjectToLong<? super K> transformer;
		final LongByLongToLong reducer;
		final long basis;
		long result;
		MapReduceKeysToLongTask<K, V> rights, nextRight;

		MapReduceKeysToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceKeysToLongTask<K, V> nextRight,
						ObjectToLong<? super K> transformer,
						long basis,
						LongByLongToLong reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Long getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToLong<? super K> transformer;
			final LongByLongToLong reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				long r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceKeysToLongTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				while (advance() != null)
					r = reducer.apply(r, transformer.apply((K) nextKey));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceKeysToLongTask<K, V> t = (MapReduceKeysToLongTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceValuesToLongTask<K, V>
					extends Traverser<K, V, Long> {

		final ObjectToLong<? super V> transformer;
		final LongByLongToLong reducer;
		final long basis;
		long result;
		MapReduceValuesToLongTask<K, V> rights, nextRight;

		MapReduceValuesToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceValuesToLongTask<K, V> nextRight,
						ObjectToLong<? super V> transformer,
						long basis,
						LongByLongToLong reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Long getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToLong<? super V> transformer;
			final LongByLongToLong reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				long r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceValuesToLongTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceValuesToLongTask<K, V> t = (MapReduceValuesToLongTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceEntriesToLongTask<K, V>
					extends Traverser<K, V, Long> {

		final ObjectToLong<Map.Entry<K, V>> transformer;
		final LongByLongToLong reducer;
		final long basis;
		long result;
		MapReduceEntriesToLongTask<K, V> rights, nextRight;

		MapReduceEntriesToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceEntriesToLongTask<K, V> nextRight,
						ObjectToLong<Map.Entry<K, V>> transformer,
						long basis,
						LongByLongToLong reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Long getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToLong<Map.Entry<K, V>> transformer;
			final LongByLongToLong reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				long r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceEntriesToLongTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey,
									v)));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceEntriesToLongTask<K, V> t = (MapReduceEntriesToLongTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceMappingsToLongTask<K, V>
					extends Traverser<K, V, Long> {

		final ObjectByObjectToLong<? super K, ? super V> transformer;
		final LongByLongToLong reducer;
		final long basis;
		long result;
		MapReduceMappingsToLongTask<K, V> rights, nextRight;

		MapReduceMappingsToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceMappingsToLongTask<K, V> nextRight,
						ObjectByObjectToLong<? super K, ? super V> transformer,
						long basis,
						LongByLongToLong reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Long getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectByObjectToLong<? super K, ? super V> transformer;
			final LongByLongToLong reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				long r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceMappingsToLongTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply((K) nextKey, v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceMappingsToLongTask<K, V> t = (MapReduceMappingsToLongTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceKeysToIntTask<K, V>
					extends Traverser<K, V, Integer> {

		final ObjectToInt<? super K> transformer;
		final IntByIntToInt reducer;
		final int basis;
		int result;
		MapReduceKeysToIntTask<K, V> rights, nextRight;

		MapReduceKeysToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceKeysToIntTask<K, V> nextRight,
						ObjectToInt<? super K> transformer,
						int basis,
						IntByIntToInt reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Integer getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToInt<? super K> transformer;
			final IntByIntToInt reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				int r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceKeysToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				while (advance() != null)
					r = reducer.apply(r, transformer.apply((K) nextKey));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceKeysToIntTask<K, V> t = (MapReduceKeysToIntTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceValuesToIntTask<K, V>
					extends Traverser<K, V, Integer> {

		final ObjectToInt<? super V> transformer;
		final IntByIntToInt reducer;
		final int basis;
		int result;
		MapReduceValuesToIntTask<K, V> rights, nextRight;

		MapReduceValuesToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceValuesToIntTask<K, V> nextRight,
						ObjectToInt<? super V> transformer,
						int basis,
						IntByIntToInt reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Integer getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToInt<? super V> transformer;
			final IntByIntToInt reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				int r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceValuesToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceValuesToIntTask<K, V> t = (MapReduceValuesToIntTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceEntriesToIntTask<K, V>
					extends Traverser<K, V, Integer> {

		final ObjectToInt<Map.Entry<K, V>> transformer;
		final IntByIntToInt reducer;
		final int basis;
		int result;
		MapReduceEntriesToIntTask<K, V> rights, nextRight;

		MapReduceEntriesToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceEntriesToIntTask<K, V> nextRight,
						ObjectToInt<Map.Entry<K, V>> transformer,
						int basis,
						IntByIntToInt reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Integer getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectToInt<Map.Entry<K, V>> transformer;
			final IntByIntToInt reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				int r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceEntriesToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey,
									v)));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceEntriesToIntTask<K, V> t = (MapReduceEntriesToIntTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}

	@SuppressWarnings("serial")
	static final class MapReduceMappingsToIntTask<K, V>
					extends Traverser<K, V, Integer> {

		final ObjectByObjectToInt<? super K, ? super V> transformer;
		final IntByIntToInt reducer;
		final int basis;
		int result;
		MapReduceMappingsToIntTask<K, V> rights, nextRight;

		MapReduceMappingsToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
						MapReduceMappingsToIntTask<K, V> nextRight,
						ObjectByObjectToInt<? super K, ? super V> transformer,
						int basis,
						IntByIntToInt reducer) {
			super(m, p, b);
			this.nextRight = nextRight;
			this.transformer = transformer;
			this.basis = basis;
			this.reducer = reducer;
		}

		public final Integer getRawResult() {
			return result;
		}

		@SuppressWarnings("unchecked")
		public final void compute() {
			final ObjectByObjectToInt<? super K, ? super V> transformer;
			final IntByIntToInt reducer;
			if ((transformer = this.transformer) != null
							&& (reducer = this.reducer) != null) {
				int r = this.basis;
				for (int b; (b = preSplit()) > 0;)
					(rights = new MapReduceMappingsToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
				V v;
				while ((v = advance()) != null)
					r = reducer.apply(r, transformer.apply((K) nextKey, v));
				result = r;
				CountedCompleter<?> c;
				for (c = firstComplete(); c != null; c = c.nextComplete()) {
					MapReduceMappingsToIntTask<K, V> t = (MapReduceMappingsToIntTask<K, V>) c,
									s = t.rights;
					while (s != null) {
						t.result = reducer.apply(t.result, s.result);
						s = t.rights = s.nextRight;
					}
				}
			}
		}
	}
	// Unsafe mechanics
	private static final sun.misc.Unsafe U;
	private static final long SIZECTL;
	private static final long TRANSFERINDEX;
	private static final long TRANSFERORIGIN;
	private static final long BASECOUNT;
	private static final long COUNTERBUSY;
	private static final long CELLVALUE;
	private static final long ABASE;
	private static final int ASHIFT;

	static {
		try {
			U = getUnsafe();
			Class<?> k = ConcurrentHashMapV8.class;
			SIZECTL = U.objectFieldOffset(k.getDeclaredField("sizeCtl"));
			TRANSFERINDEX = U.objectFieldOffset(k.getDeclaredField("transferIndex"));
			TRANSFERORIGIN = U.objectFieldOffset(k.getDeclaredField("transferOrigin"));
			BASECOUNT = U.objectFieldOffset(k.getDeclaredField("baseCount"));
			COUNTERBUSY = U.objectFieldOffset(k.getDeclaredField("counterBusy"));
			Class<?> ck = CounterCell.class;
			CELLVALUE = U.objectFieldOffset(ck.getDeclaredField("value"));
			Class<?> sc = Node[].class;
			ABASE = U.arrayBaseOffset(sc);
			int scale = U.arrayIndexScale(sc);
			if ((scale & (scale - 1)) != 0)
				throw new Error("data type scale not a power of two");
			ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
		}
		catch (Exception e) {
			throw new Error(e);
		}
	}

	/**
	 * Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. Replace with a simple call to Unsafe.getUnsafe when integrating
	 * into a jdk.
	 *
	 * @return a sun.misc.Unsafe
	 */
	private static sun.misc.Unsafe getUnsafe() {
		try {
			return sun.misc.Unsafe.getUnsafe();
		}
		catch (SecurityException tryReflectionInstead) {
		}
		try {
			return java.security.AccessController.doPrivileged(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
				public sun.misc.Unsafe run() throws Exception {
					Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
					for (java.lang.reflect.Field f : k.getDeclaredFields()) {
						f.setAccessible(true);
						Object x = f.get(null);
						if (k.isInstance(x))
							return k.cast(x);
					}
					throw new NoSuchFieldError("the Unsafe");
				}
			});
		}
		catch (java.security.PrivilegedActionException e) {
			throw new RuntimeException("Could not initialize intrinsics",
							e.getCause());
		}
	}
}
